Weekly seminars 2024/2025
Our weekly seminars take place on Thursdays at 13:00 local DST (12:00 UTC winter time, 11:00 UTC summer time) in AMU Astronomical Observatory building at 36 Słoneczna Street. The person responsible for organization of seminars is Tomasz Kwiatkowski, to whom all questions regarding dates/subjects, as well as the video equipment needed should be directed.
To allow persons from outside of Poznań to participate in our seminars, under selected talks, we shall provide links to the MS Teams session. To join our meeting in a video conference mode (without logging in), one has to click on the link in the Google Chrome (it may not work with other browsers), enter the first and last name and wait for the acceptance of the organizer. Alternatively, one can use a dedicated MS Teams application.
Talks in previous years:
2024/2025, 2023/2024, 2022/2023, 2021/2022, 2020/2021, 2019/2020, 2018/2019, 2017/2018, 2016/2017
Previous talks in 2024/2025:
12th June 2025
Student’s presentations (AOI AMU)
of a space mission to a selected object of the Solar System. The mission concepts were prepared as part of the course “Solar System Astronomy” conducted by Dr. Justyna Gołębiewska using the Problem-Based Learning method.
Language: Polish, lecture in-person
5th June 2025
Nicolas Erasmus (SAAO, South Africa)
The South African Astronomical Observatory (SAAO) continues to play an important role in the global effort to observe and characterise near-Earth asteroids (NEAs). With an observing site located near the town of Sutherland, the SAAO hosts a range of telescopes (1–10 m class) equipped for photometry, spectroscopy, and polarimetry. The robotic 1.0-m Lesedi telescope enhances rapid-response capabilities, enabling same-night follow-up of newly discovered NEAs. SAAO has contributed to numerous international campaigns coordinated by the International Asteroid Warning Network (IAWN), including the “2012 TC” (Reddy et al. 2019), “Apophis” (Reddy et al. 2022), and “2023 DZ2” (Reddy et al. 2024) exercises. SAAO facilities were also involved in ground-based monitoring of NASA’s DART impact on Dimorphos (Fitzsimmons et al., in review). With the recent installation of one of the southern nodes of the Asteroid Terrestrial-impact Last Alert System (ATLAS; Tonry et al. 2018) and the development of the Intelligent Observatory (IO) initiative (Potter et al. 2024), SAAO is well positioned to support the increasing demand for NEA follow-up as survey discoveries accelerate.
This talk will present an overview of SAAO’s NEA-focused observing infrastructure and highlight selected results from recent campaigns. It will also outline plans to better utilise underused facilities and strengthen SAAO’s role in the international NEA characterisation community.
Language: English, lecture remote
29th May 2025
Martin Solar (AOI AMU)
Supernovae are very energetic explosions as the final fate for some stars. Specifically, massive stars (> 8 Msol) are expected to end their life as core-collapse supernovae. The importance in understanding how massive stars form, evolve and explode as supernovae is because they produce heavy elements and halt the star formation in the interstellar medium, so they have a profound impact on galaxy evolution. In order to constrain the progenitor properties of supernovae, their interstellar medium environments are studied. However, the spatial resolution scale is essential for distinguishing progenitor environments directly from supernova locations. This presentation is aimed to show high-resolution observations at scales of giant molecular clouds at supernova environments. To do so, ALMA and MUSE observations are used as proxies of cold molecular gas and warm ionised gas, respectively. The multiwavelength approach gives us a complete comprehension on the conditions from which supernovae explode and understand better their progenitor properties from their molecular gas depletion time environments.
Language: English, lecture in-person
22nd May 2025
mgr José David Balseca Cisneros (Universidad de Alicante, Spain)
We present a study focused on the detection of large, distant objects in the Solar System, specifically those of planetary size located beyond 100 AU. This search is motivated by models of the primordial planetesimal disk, which suggest that the early Solar System may have hosted hundreds to thousands of Pluto-sized bodies, and potentially a few Mars-sized or larger objects. These predictions, consistent with both dynamical simulations and accretion models, raise the possibility that some of these distant bodies may still exist but remain undetected.
To explore this, we analyze deep-sky images collected over the past four years by the 0.68-m Schmidt telescope at Mt. Bigelow and the 1.5-m Cass telescope at Mt. Lemmon, both part of the Catalina Sky Survey. Our approach involves co-adding wide-field unfiltered images from different nights to increase the sensitivity and reveal faint, slowly moving sources. Image alignment is performed using the Tycho Tracker software, and source detection is carried out via Python codes based on the Astropy library and a matched-filter technique. This stacking method allows us to reach a limiting magnitude of V ≈ 21.5, sufficient to detect distant objects in the trans-Neptunian region. We then compare source positions across different epochs to identify candidate moving objects. For those showing consistent motion, we determine preliminary orbits using the software Find Orb, which enables orbital fitting even with sparse and low-cadence data sets. This step is essential for distinguishing real distant Solar System bodies from false positives or artifacts.
The methodology described here offers a robust and scalable framework that can be applied to other panoramic multi-epoch surveys, improving our ability to uncover faint and distant members of the Solar System population.
Language: English, lecture in-person
15th May 2025
Priyanka Jalan (CAMK, Warsaw)
We introduce FLAME, a machine learning algorithm designed to fit Voigt profiles to HI Lyman-alpha absorption lines using deep convolutional neural networks. FLAME integrates two algorithms: the first determines the number of components required to fit absorption lines, and the second calculates the Doppler parameter b, the HI column density NHI, and the velocity separation of individual components. For the current version of FLAME, we trained it on low-redshift forests observed with the Far Ultraviolet gratings of the COS aboard the HST. Drawing on this data, we trained FLAME on ~1M simulated Voigt profiles, forward-modeled to mimic absorption lines observed with HST-COS, to classify lines as either single or double components, and then determine Voigt profile fitting parameters. FLAME shows impressive accuracy on the simulated data by identifying more than 98% (90%) of single (double) component lines. It determines b values within 15 (18) km/s and log NHI cm2 values within 0.3 (0.8) for 90% of the single (double) component lines. However, when applied to real data, FLAME’s component classification accuracy drops by ~10%. Despite this, there is a reasonable agreement between the b and NHI distributions obtained from traditional Voigt profile fitting methods and FLAME’s predictions. Our mock HST-COS data analysis, designed to emulate real data parameters, demonstrated that FLAME could achieve consistent accuracy comparable to its performance with simulated data. FLAME’s performance validates the use of machine learning for Voigt profile fitting, underscoring the significant potential of machine learning for detailed analysis of absorption lines.
Language: English, lecture remote
8th May 2025
Joanna Mikołajewska (CAMK, Warsaw)
Accreting white dwarf binaries are the most common interacting binaries in the Universe. The accretion leads to various outburst phenomena; among the most spectacular are thermonuclear nova explosions recurring with timescales from months to millions of years. The thermonuclear novae are also one of the most violent stellar explosions, contributing to galactic chemical evolution. Symbiotic novae are those with evolved giant donors. They are very suitable to study nova life cycles, because they have the higher accretion rates and shorter recurrence timescales than those with less evolved donors. I am going to present the state-of-the-art in understanding of them with emphasis on the recent results and discoveries.
Language: English, lecture in-person
24th April 2025
Grzegorz Pietrzyński (CAMK, Warsaw)
My main motivation is to provide detailed information about the new Polish observing facility: the Rolf Chini Cerro Murphy observatory in Chile. The observatory is located in front of the construction site of the biggest telescope in the world, the ELT and offers arguably the best observing conditions on our planet. I will present the current status of the instrumentation at the observatory together with our ambitious plans to expand its observing capabilities in the near future. Selected results obtained so far and recently started scientific projects will be discussed.
I will also present our results in the software development, instrumental projects, and first attempts in commercialisation. Finally I will mention several aspects of using the big potential of this observatory in international, interdisciplinary projects and outreach.
Language: English, lecture in-person
10th April 2025
Szymon Kozłowski (Astronomical Observatory, University of Warsaw)
Oxygen is the third most common element in the Universe. It can be found virtually anywhere on Earth (air, water, rocks) and in the Solar System. Because oxygen exists in the form of three stable isotopes, their relative abundances in meteorites provide us with information on their formation locations. By studying oxygen isotope ratios you can tell if a meteorite is a piece of rock from Earth, Mars, or an asteroid. I am going to review the role of oxygen in meteoritic studies.
Language: English, lecture in-person
27th March 2025
Krzysztof Langner (AOI AMU)
In 2022, the DART mission spacecraft impacted Dimorphos, the smaller asteroid in the Didymos-Dimorphos binary system. This system is the target of the European Space Agency Hera mission, with the Hera spacecraft scheduled to arrive in 2026 to conduct further post-impact research. The DART impact ejected a large number of rocks and boulders into the space surrounding both asteroids, some of which are re-impacting the surfaces of Didymos and Dimorphos. In this talk, I will discuss the potential effects of these boulder impacts on the surface of Didymos and their implications for the Hera mission.
Language: English, lecture in-person
27th February 2025
Oleh Ryzhov (AOI AMU)
In this talk, I will briefly present the basics of how spectroscopic data can be used to identify the ionization sources in the galaxies (young stars, planetary nebulae, AGNs). This will be followed by the story of how the Extragalactic Team of Poznań applied these techniques to find out the dominant ISM removal mechanism in dusty ellipticals, selected from the Galaxy And Mass Assembly survey, which consequently resulted in the paper, published recently in Astrophysical Journal Supplement Series. Lastly, the new projects and ideas regarding the topic will be discussed.
Language: English, lecture in-person
23rd January 2025
Monika Kamińska (AOI AMU)
Over the past few years the RBT (PST2) telescope of Adam Mickiewicz University, located in Winer Observatory in Arizona, has been involved in observations of Earth orbiting artificial satellites within the European sensor network of the EU Space Surveillance and Tracking Partnership (EU SST). In 2024 the network has implemented a central observation planning system (COPLA) for all optical and radar sensors in the network, which required significant adaptations of our observing system. I present the current status of the telescope, recent changes and our experience with the EU SST system.
The talk will be technical rather than scientific.
Language: English, lecture in-person
16th January 2025
Michał Żejmo (Institute of Astronomy, University of Zielona Góra)
In 2021, the Janusz Gil Institute of Astronomy, University of Zielona Gora was equipped with a system consisting of two telescopes – a main telescope of CDK design with a diameter of 20 inches and an auxiliary telescope of RASA design with a diameter of 11 inches.The two telescopes form a single system for both deep space observations and observations related to the Space Surveillance and Tracking (SST). The system was tested in Spain for a year, then transported to the hosting site in Chile.
In my presentation, I will discuss the experience of using the system, its involvement and achievements in scientific projects, its application in student education and the popularisation of astronomy, as well as future plans to expand the system with new telescopes and create a RemoteObservatory of the University of Zielona Góra.
Language: English, lecture in-person
9th January 2025
Short scientific communications (AOI AMU)
- Antoine Choukroun, in-person, 10 min + 5 min for questions
- Justyna Olszewska, in-person, 10 min + 5 min for questions
- Jakub Tokarek, in-person, 10 min + 5 min for questions
- Julia Pietrzak, Polish, in-person, 10 min + 5 min for questions
- Jakub Tokarek, in-person, 5 min: current status of the Borowiec telescopes
19th December 2024
Dominik Cieślak (University of Maryland Baltimore County)
The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission provides critical insights into the exchange of carbon dioxide between the ocean and atmosphere. In addition, PACE data help clarify how airborne particles (aerosols) influence the growth of phytoplankton in surface waters. This improved understanding supports practical applications, such as pinpointing the extent and duration of harmful algal blooms—information valuable for both economic and public health considerations. Building on decades of NASA’s Earth observations, PACE promises to expand our perspective on the planet’s health, ensuring that researchers, policymakers, and communities benefit from its findings for many years to come.
Language: English, lecture in-person
12th December 2024
Cyrielle Opitom (School of Physics & Astronomy, The University of Edinburgh)
Comets are pristine relics of the protoplanetary disk, where the planets formed and evolved, and preserve in their ices important clues about the early solar nebula. When a comet approaches the Sun, the ices it contains sublimate to form a huge atmosphere of gas and dust called the coma. Spectroscopy of cometary coma provides invaluable cues about solar system formation. However, comets are notoriously difficult to observe. They are extended objects, whose emission lines can be difficult to detect using ground-based instrumentation. In this seminar, I will explore how new and upcoming UV/optical spectrographs and IFUs are essential to study the composition of comets, understand their activity, and investigate the origin of species in their coma.
Language: English, lecture online
5th December 2024
Short scientific communications (AOI AMU)
- Jakub Nadolny, English, remotely, 10 min + 5 min for questions
- Martin Solar, English, in-person, 10 min + 5 min for questions
- Fabian Kaczmarek, English, in-person, 10 min + 5 min for questions
- Oleh Ryzhov, English, in-person, 10 min + 5 min for questions
28th November 2024
Short scientific communications (AOI AMU)
- Milagros Colazo, English, in-person, 10 min + 5 min for questions
- Michał Michałowski, English, in-person, 10 min + 5 min for questions
- Sofiia Mykhailova, English, in-person, 10 min + 5 min for questions
- Paweł Koleńczuk, English, in-person, 10 min + 5 min for questions
21st November 2024
Arkadiusz Berlicki (University of Wrocław, Centre of Scientific Excellence – Solar and Stellar Activity)
Spectroscopic observations and modelling of the solar atmosphere are important tools for understanding its structure and physical processes. Solar atmosphere is an interface between solar interior and the heliosphere, including Earth and its surrounding. Therefore, detailed analysis of the atmospheric composition, magnetic structure, energy transport, heating and dynamics is necessary for proper description of interactions between the processes occurred in the solar interior with those observed in the interplanetary space and related with the Sun. All these processes are significantly stronger during maximum of solar activity. Energetic solar active phenomena, in particular flares or coronal mass ejections (CMEs) significantly increase the radiation and fluxes of energetic particles, which contribute to the so called “Space Weather”.
Analysis of the solar active events is important and require special techniques of observations and simulations. One of the method which seems to be most perspective is non-equilibrium plasma spectroscopy combined with NLTE modelling of different active phenomena. With these methods we hope to understand solar flares, prominences, Ellerman bombs, CMEs and other events as most violent eruptions potentially affecting our planet. Recently, newly obtained solar microwave data from ALMA interferometer provide a new basis for a better understanding of these events. Our research can be also extended for stellar flares commonly observed on active late-type stars where similar, or bigger, sudden eruptions can affect potential exoplanets orbiting around these stars.
Language: English, lecture in-person
14th November 2024
Krzysztof Kamiński, Justyna Gołębiewska, Edwin Wnuk (AOI AMU)
We present two methods for predicting the time of re-entry of artificial satellite into the Earth’satmosphere.
The first method utilizes astrometric results from optical observations of objects in low Earth orbits (LEO) collected over the two months preceding the predicted re-entry time. These observations were carried out using a global network of telescopes belonging to the Astronomical Observatory of AMU and the company 6ROADS. These data allow for refining the orbit, atmospheric drag parameters and ballistic coefficient, significantly increasing the accuracy of determining the final re-entry time.
The second method is based on the analysis of historical data from the US Space Force orbital catalog and orbital data obtained from our observations. Matching the propagation results with the updated orbital catalog, enriched with data from the new observations, enables the precise determination of the ballistic coefficient, which in turn allows for more accurate re-entry predictions.
Language: Polish, lecture in-person
7th November 2024
Andrzej Szary (Institute of Astronomy, University of Zielona Góra)
Over the past half-century since their discovery, pulsar studies have significantly advanced our understanding of neutron star physics, general relativity, the Galactic gravitational potential and magnetic field, the interstellar medium, celestial mechanics, and even cosmology. However, one major mystery in pulsar astronomy remains unresolved: the mechanism behind their radio emission. Although the discovery of pulsars was based on this property, there is still no consensus on the fundamental process driving it. Pulsar radio emission is characterized by highly periodic pulses, with individual pulses composed of subpulses that often exhibit systematic variations in position or intensity— a phenomenon known as drifting subpulses (Drake & Craft, 1968). In recent years, significant progress has been made in both the observational and theoretical understanding of drifting subpulses. On one hand, a physical justification for drift around the magnetic axis has been proposed (Szary et al. 2017), while on the other hand, an alternative model involving plasma drift around the rotation axis has gained traction (see, e.g., Basu et al. 2020; Basu et al. 2022). In this talk, I will present a research plan and initial results from a comprehensive investigation aimed at resolving this contradiction and uncovering the true nature of the drifting subpulse phenomenon.
Language: English, lecture in-person
24th October 2024
prof. UAM dr hab. Tomasz Kwiatkowski (IOA UAM)
In recent years, the development of smart telescopes has made it easier for amateur astronomers to capture images of deep sky objects. These innovative instruments have a built-in imaging sensor and computer, which can automatically adjust their position and focus without any human intervention. They are usually controlled by a smartphone app, which can download images in real time through WiFi. In this talk, I will present the Seestar S50, a smart telescope that will soon be part of our observatory’s educational equipment. I will discuss its technical capabilities and its application in student education, assuming it is used locally, at our observatory’s park.
Language: English, lecture in-person
10th October 2024
Agnieszka Kryszczyńska (AOI AMU)
Language: Polish, lecture in-person
Previous talks in 2023/2024:
20th June 2024
Student’s presentations (AOI AMU)
Language: Polish, lecture in-person
13th June 2024
Bartosz Pieterek (Polish Geological Institute, Geohazards Research Unit, AMU)
Planetary sciences are currently one of the most developing branches of industry and science which meet humanity’s aspirations to explore Space. Just after the Moon, Mars is one of the most trailblazing research fields, as it constitutes a critical step forward in planetary exploration. Nevertheless, a detailed Martian evolution is fundamentally unknown and this carries with it significant consequences for upcoming exploration missions.
Although it is widely accepted that Mars’s evolution has been mainly controlled by magmatism expressed on the surface by volcanic centers, the ongoing acquisitions of datasets provide great advances in Martian surface visualization increasing our capability of investigating volcanic landforms that have been previously overlooked. During this contribution, the presenter will provide an integrated portrait of Amazonian-aged Martian volcanism, especially focusing on the small-scale landforms across Mars whose investigation may breakthrough our understanding of the most recent magmatic processes.
Language: English, lecture in-person
6th June 2024
Antoine Choukroun (AOI AMU)
Determining the physical parameters of asteroids is a complex yet crucial task. Size determinations of asteroids can differ from source to source by as much as 30%. It is going to influence theoretical. studies of dynamical and thermal effects affecting asteroids. For example, it can lead to 90% uncertainty in density determinations.
In our research, we focused on studying several main-belt asteroids using high-quality data. Initially, we fitted lightcurves in the visible range using convex inversion obtaining precise information on the spin axis and an initial shape model. Subsequently, we used these results as input for another modelling technique called Convex Inversion Thermophysical Model (CITPM). CITPM optimizes the model based both on lightcurves and thermal data, providing output such as surface roughness, temperature distribution, thermal inertia, and asteroid size. Additionally, by fitting the initial models to stellar occultation observations, we determined asteroid sizes with another recognized precise method. This revealed a good agreement with the sizes determined by CITPM, enhancing the credibility of its other output parameters.
Language: English, lecture in-person
23rd May 2024
Emil Wilawer (AOI AMU)
Traditional phase curves are created based on the maximum (or average) brightness of the brightness curve at a given phase angle, using dense ground data. However, they are available for a relatively small number of objects. On the other hand, sky surveys, such as Gaia or ATLAS, provide data for a large number of objects, but the data are spread out over time and there are significant changes in the geometry of the observations, making it difficult to obtain high-quality phase curves based on these data alone.
By combining both types of data, it is possible to obtain high-quality phase curves for a large number of objects. In addition, by applying this method to survey data using different filters, it is possible to study the effect of the filter used on the observation results. With an exponentially increasing number of incoming data and new, larger surveys of the sky planned, this method makes it possible to make efficient use of such data and obtain previously unavailable information about asteroids.
Language: English, lecture in-person
16th May 2024
Vincent Robert (IMCCE & IPSA, France)
The NAROO program has been created at Paris Observatory, Meudon, as a unique centre dedicated to the digitization and the analysis of old astro-photographic plates for scientific purposes, only.
The renewed interest about photographic plates concerns the expansion of the database of transient objects evolving in time, since 1) digitization now makes it possible to measure images with a high level of accuracy and to identify all the available objects, 2) the arrival of the Gaia reference catalogs allows to realize reductions for past observations with today accuracy. The information extracted from such materials can be of an astrometric, photometric, and spectroscopic nature, when not purely imaging, with consequences in planetology, near-Earth asteroid risk assessment, astrophysical phenomena, and general relativity, to mention but a few. We will present technical details about the installation, then results of the first large scientific campaigns derived form planetary plates (Jupiter) and Sky surveys plates (NEO precoveries).
Language: English, lecture online
9th May 2024
Gracjan Maciejewski (IA UMK)
Hot Jupiters, giant planets on tight orbits, have been perceived as loners devoid of planetary companions in close orbital proximity. However, recent discoveries based on space-borne precise photometry have revealed that at least some fraction of those giant planets coexist with low-mass planets in compact orbital architectures. The origin of hot Jupiters is a long-lasting question in the planetary formation and evolution theory. Three main pathways are proposed to explain the formation of those planets: in situ formation, disk migration, and high eccentricity tidal migration. The question of the dominant path still needs clarification, and the answer is hidden in the architectures of those systems. In my talk, I will share the results of an ongoing project aimed at searching for transiting planetary companions to hot Jupiters, including a tale on the WASP-84 system.
Language: English, lecture in-person
25th April 2024
Karolina Dziadura (IOA UAM)
Asteroid studies are pivotal in unravelling the mysteries of the Solar system’s formation, as well as understanding planetary systems and Earth’s water origins. This research focused on determining asteroid sizes through occultation data and devising an effective method to leverage the precise Gaia DR2 and DR3 asteroid data for analyzing the Yarkovsky effect.
Leveraging Gaia’s robust asteroid astrometry, alongside radar and terrestrial observational data, our research advances orbit computation efforts, with a special emphasis on identifying non-gravitational transverse accelerations. We introduced and validated an innovative astrometry weighting scheme, which factors in diverse observational variables, thereby enhancing data reliability. Ultimately, the analysis of the Yarkovsky effect on asteroids allowed for determining their densities, providing crucial parameters for understanding the physical properties and evolution of these minor celestial bodies.
The advent of Gaia’s stellar measurement accuracy has revolutionized the observation of occultation events, granting us deeper insights into asteroid characteristics. This is particularly critical for potentially hazardous asteroids (PHAs), where exact size and orbit determinations are pivotal for impact monitoring. The assessment of the Yarkovsky effect has facilitated the determination of asteroid densities, shedding light on these minor celestial bodies’ physical properties and their evolutionary trajectories.
Additionally, this study delves into the utilization of occultation data, integrating its inherent uncertainties to accurately ascertain asteroid sizes. The meticulous computation of orbits, employing various observational spans, and the analysis of a few PHAs underscore the research’s contribution to precise orbit prediction. By factoring in phenomena such as the Yarkovsky effect, we have significantly refined orbit determination processes, marking substantial progress in the realm of PHA monitoring.
Language: English, lecture in-person
18th April 2024
Krzysztof Langner (IFAC-CNR & Università di Padova & AOI AMU)
In 2022 the DART mission spacecraft impacted the asteroid Dimorphos, the secondary body of the binary Didymos system, ejecting a large number of dust particles, rocks and boulders. The ESA Hera mission will reach the system in 2026 for post–impact studies and possible detection of orbiting fragments. We investigate the long term dynamics of the large boulders ejected by DART to test if any of these objects survive in orbit until the arrival of the Hera mission. To model the dynamics of the boulders we use a numerical model which includes the gravity of non-spherical Didymos and Dimorphos, the solar gravity and the radiation pressure. The SPICE kernels are used to define the correct reference frame for the integration. The dynamics of the boulders is highly chaotic and 1% of the initial boulders survive at least for 4 years on quasi–stable orbits. These orbits are characterised by wide oscillations in eccentricity in antiphase with those in inclination (including spin flips), a mechanism similar to the Kozai one. This behaviour may protect these bodies from close encounters with both asteroids. We also compute the distribution on the surfaces of the asteroids of sesquinary impacts which may influence the dust emission, after the initial DART impact, and the surface composition of the asteroids. The probability of observing boulders by the mission Hera is small but not negligible and an almost constant flux of escaping boulders is expected in the coming years since their lifetime after the DART impact covers a large time interval. Most of re–impacts on Dimorphos occur in the hemisphere opposite to the impact site, preferentially close to the equatorial plane.
Language: English, lecture online
11th April 2024
Paweł Kankiewicz (UJK)
Asteroids in retrograde orbits, known briefly as retrograde asteroids, have relatively short lifetimes in the Solar System. It can be assumed that almost all of them are orbiting in highly chaotic trajectories. Quantitatively, it is possible to estimate this using suitable parameters that measure the rate of chaotic expansion of close trajectories. Since we are mostly dealing with problems solved strictly numerically, an obvious solution is the application of Lyapunov indicator and a related parameter known as MEGNO (Mean Exponential Growth factor of Nearby Orbits). In the current work, I would like to present a novel and very flexible software that allows the simulation, quantitative estimation and imaging of the chaotic behaviour of retrograde asteroids, designed using astronomical Python language modules. The comprehensive solution allows flexible use of astronomical databases, instant updating with new observational data, testing of different perturbation models and linking results to observational errors.
Language: English, lecture in-person
14th March 2024
Anna Marciniak (AOI AMU)
Asteroid Justitia is a special main-belt object, being an extremely red body with a steeper spectral slope than any other D-type asteroid. Conversely, its spectral and polarimetric properties resemble organics-rich Centaurs and trans-Neptunian objects. For this reason, it was recently chosen as a main target of the MBR space mission.
It is crucial for space mission planning and operations to have in advance the best estimate of the target size, spin, shape, and properties of the surface. In particular, the size determination was in high demand before the extensive stellar occultation campaign in August 2023, for stations deployment and observation planning.
We utilised multiple lightcurves from our campaign on slow rotators and from the literature to reconstruct the spin and shape of Justitia via lightcurve inversion. Then we applied the Convex Inversion Thermophysical Model to simultaneously optimise the fit to visible lightcurves and to thermal data from infrared space observatories. We will present the most precise physical model of Justitia possible before the occultation campaign.
Language: English, lecture in-person
7th March 2024
Aleksandra Leśniewska (AOI AMU)
Dust is a key component of the interstellar medium. The mechanism of dust removal from galaxies has not been completely understood yet. I will address this issue by the analysis of 2050 dusty early-type galaxies, in which star formation has a much lower rate than what their masses could imply, yet an unnaturally large amount of dust is observed. The analysis is conducted on a sample that differs from previous works not only in the number of objects, but most of all in a wider range of parameters. Based on already published data (GAMA and eFEDS) as well as on never-before-published data from LOFAR we are able to determine mechanisms which are responsible for the observed dust loss and estimate the dust removal timescale observed in dusty early-type galaxies.
Language: English, lecture online
1st February 2024
Edwin Wnuk (AOI AMU)
Language: Polish
25th January 2024
Jakub Nadolny (AOI UAM)
In this talk, I will focus on LGalaxies2020 semi-analytic models run on top of Millennium Simulations. The Millennium Simulations provide a cosmological volume (with a side length of ~700 Mpc) in a concordance LCDM cosmology.
In particular, I will focus on a selected sample of early-type galaxies, including their history, to address how and why these galaxies have quenched their star formation. One crucial factor in the quenching of star formation involves the elimination of the cold interstellar medium (ISM) from a galaxy. However, it is not yet clear which quenching mechanisms are dominant. Here, we study the decline in atomic hydrogen and dust mass in a statistically significant sample of massive (M*>10^10Msun) simulated early-type galaxies in a redshift range between 0.02 and 0.32. We find agreement with previous observational works, considering the timescales of ISM removal. Furthermore, we show that black hole growth, together with radio mode accretion and its feedback, controls the amount of cold and hot gas in galaxies, leading to quenching. This is a consequence of a merger event at some point in the evolution of individual galaxies. Moreover, we recover the observed relation between dust mass and star formation rate for actively star-forming galaxies, as well as for passive early-type galaxies. We conclude that merger-driven morphological transformation is a key event that shapes the evolution of simulated galaxies.
This work is a continuation of a series of papers about ‘The fate of the interstellar medium in early-type galaxies’ (see Michałowski et al. 2019, 2024; Leśniewska et al. 2023).
Language: English, lecture online
18th January 2023
Przemek Mróz (OA UW)
Gravitational-wave detectors – LIGO, Virgo, and KAGRA – have revealed a population of massive black holes whose origin is still a subject of vigorous debate. Understanding the population of black holes in the Milky Way is therefore of key importance for understanding and putting into the astrophysical context the LIGO/Virgo/KAGRA discoveries.
Gravitational microlensing remains the only viable technique which enables us to detect and directly measure masses of isolated stellar remnants, especially neutron stars and black holes. In this talk, I will present the recent advancements in the field of gravitational microlensing, which have led to the discovery of the first isolated stellar-mass black hole in the Milky Way and which will pave the way for future similar discoveries. I will present how astrometric and interferometric observations of gravitational microlensing events allow us to detect and characterize isolated neutron stars and black holes. Finally, I will discuss whether black holes of different sizes can make up dark matter.
Language: English
11th January 2023
Sofiia Mykhailova (AOI AMU)
The project at hand is centered on observational studies of primitive asteroids, addressing the challenges posed by the lack of spectral information about their surface compositions. While most compositional studies have focused on visible-near-infrared (VIS-NIR) wavelengths, the study highlights the distinct near-ultraviolet (NUV) absorption feature in low-albedo asteroids, suggesting variations in surface composition related to iron content and hydration history. The significance of NUV studies is underscored by their potential to detect hydrated minerals and organic materials, providing crucial insights into asteroid history and the effects of space weathering. In this talk I will present the first results of observations of asteroids in NUV-VIS range, obtained using the 10.0-m SALT telescope in South Africa, during November-December 2023.
Language: English
21st December 2023
Dominik Cieślak (University of Maryland Baltimore County)
This presentation provides an overview of the techniques and instruments employed in the remote sensing aerosols in Earth’s atmosphere. The discussion will focus on the role of remote sensing in enhancing our comprehension of cloud development and its direct correlation with air pollution. The engineering segment of the presentation will particularly accentuate the design of the HARP instruments, including the environmental tests that these satellite instruments must undergo before being considered for NASA space missions.
Language: English
14th December 2023
Paolo Tanga (Observatoire de la Côte d’Azur, Nice, France)
The traditional view of a clear separation between astrometry of asteroids, and observations devoted to determine their physical properties (shape and rotation for instance) is challenged by data collected by the Gaia mission of ESA. The reason is that Gaia astrometry, at least for a fraction of the asteroids, contains the signature of effects related to their orientation in space, their size, or the presence of satellites. In this situations, an optimal exploitation of the data includes the optimal modeling of such physical characteristics, a complex task whose implications have still to be fully exploited. In this talk I will detail in particular the possible signature of binarity, an ongoing search. I will also recall the interest of the more indirect, but strong impact of Gaia on the asteroid occultation technique, that has never been so powerful before.
Language: English
7th December 2023
Piotr A. Dybczyński (AOI AMU)
Authors:
Piotr A. Dybczyński, Małgorzata Królikowska-Sołtan, Przemysław Bartczak, Edyta Podlewska-Gaca, Krzysztof Kamiński, Jakub Tokarek, Krzysztof Langner, Jos de Bruijne
Abstract:
In the long-period comets dynamical studies we have to cope with the increasing knowledge on the stars that can act as their perturbers. As a part of our long standing project we made available two databases: stellar: https://pad2.astro.amu.edu.pl/StePPeD/ and cometary: https://pad2.astro.amu.edu.pl/CODE/
We found several important stellar perturbers but the most important seem to be the star HD 7977. According to the Gaia DR3 astrometry this star (of 1 solar mass) passed near the Sun 2.47 Myr ago at a distance of 0.011 pc (~2300 au) ! We discuss the uncertainty of this result, its possible consequences and show some examples of its impact on the Solar System small bodies dynamics.
Language: English
30th November 2023
Paweł Koleńczuk (AOI AMU)
Very small Near-Earth asteroids (diameter less than 200 m), due to their size, can usually be observed for a short time during close approaches to the Earth, after which it is often necessary to wait several or dozens years for another approach. Therefore, not many of these objects are well characterized, for example, only about 1% of them have a designated taxonomic type. I am going to present the issues of observation and methods of obtaining colour indices and taxonomic type of NEOs
Language: English
23rd November 2023
Fabian Kaczmarek (AOI AMU)
Symbiotic stars (SySts) represent an example of close binary systems in which a hot, compact object, most often a white dwarf, accretes material from a cool component, usually an evolved red giant. Such systems are characterized by the longest orbital periods among interacting binary stars. In order to spatially resolve the components of SySts, high angular resolution of astronomical observations is required. Optical, long-baseline interferometry provides an ideal method for this task, as it allows to directly and very precisely study such binary stellar systems, e.g. measure the radii of their components with spatial resolution of the order of milli-arcseconds. Here I would like to present the results of analysis of the interferometric observations that were made for the symbiotic recurrent nova RS Ophiuchi. The data was obtained using the ATISSE/VLTI instrument. I was able to determine the size of the emitting regions and – as the data was obtained for two different observational epochs – follow the expansion of the ejected matter.
Language: English
16th November 2023
Karri Muinonen (University of Helsinki)
Photometric inversion has been extensively used to infer the spin and shape properties of asteroids from dense ground-based lightcurves. The high-precision sparse photometry provided by Gaia has enabled studies of asteroid phase functions. Gaia Data Release 3 (DR3) contains photometric observations of more than 150,000 asteroids (Tanga et al., Astron. & Astrophys. 674, A12, 2023). We consider the rotation periods, pole orientations, shapes, and photometric slopes for over 22,000 asteroids that have at least 25 Gaia observations, using ellipsoid and general convex shape models. We characterize the uncertainties of the solutions by using a Markov chain Monte Carlo approach (Muinonen et al., Astron. & Astrophys. 642, A138, 2020). We complement the photometric slopes with DR3 spectroscopy (Gaia Collaboration, Astron. & Astrophys. 674, A35, 2023). The full spectroscopic dataset includes 57490 asteroids. After selecting asteroids with both spectra and photometric slopes and after filtering for the highest-quality spectral points, we are left with 5783 asteroids. Constructing a feed-forward, fully connected neural network, we find that the most reasonable classification (maximum number of classes with high overall accuracy) comes from classifying the asteroids into the taxonomic classes C, S, X, and D. The accuracy of the classification is about 80%. Finally, classification with only the spectroscopic parts would decrease the accuracy.
Language: English
9th November 2023
Jolanta Grala-Michalak (Faculty of Mathematics and Computer Science AMU)
Language: Polish
26th October 2023
Justyna Olszewska (AOI AMU)
In stellar research, spectroscopy and photometry play a key role in obtaining complex insights into stellar properties and processes. My study focuses on the analysis of spectroscopic data obtained from the Global Astrophysical Telescope System (GATS) for selected Galactic Cepheids. I determined changes in atmospheric parameters and chemical composition in relation to the pulsation phase. To complete my study, I also analyzed photometric data collected by the TESS space observatory. The combination of spectroscopy and photometry provides a more comprehensive understanding of Cepheids and their characteristics.
Language: English
12th October 2023
Seminar cancelled (celebrations of the 30th anniversary of the Faculty of Physics)
Previous talks in 2022/2023:
22nd June 2023
Bartłomiej Zgirski (CAMK Warsaw)
Distance determinations are among the fundamental tasks in astronomy. They not only allow for the proper calibration of the energetics of different astrophysical phenomena but are also crucial for determining important cosmological parameters, including the Hubble parameter.
There is no single universal method for cosmic distance determinations. In practice, we work with the cosmic distance ladder, where short-range methods calibrate zero points of long-range methods. The most precise and accurate distances to astrophysical objects and systems are obtained using geometric methods such as parallax or relying on the analysis of detached eclipsing binary stars. These methods allow us to anchor our secondary methods applied in the determination of distances to nearby galaxies. Classical Cepheids, the tip of the Red Giant Branch, and carbon stars are representatives of the secondary distance indicators. The final rung of the ladder is associated with distances to galaxies in the Hubble flow obtained using properly calibrated luminosities of supernovae.
An important problem in modern astronomy is the discrepancy between values of the Hubble parameter obtained from observations of the early and late Universe, known as the Hubble tension. Namely, the model-dependent value based on the analysis of the cosmic microwave background observed with the Planck space observatory does not agree with the value based on the determination of the parameter using supernovae calibrated by classical Cepheids. This puzzling issue could be associated with the need to check for unaccounted systematic errors of the used distance determination methods or the necessity to revise the Lambda cold dark matter cosmological model. Thus, it is important to use, in parallel, different distance determination methods at the same scales in order to check for potential systematic biases that depend on the used method.
As a member of the Araucaria Project, an international team of astronomers working on the cosmic distance scale, I will highlight the methods we use. I will also present a new Polish observatory in the Chilean Atacama Desert that will allow us to gather both photometric and spectroscopic data in the optical and near-infrared domains for the purpose of our project and beyond.
Language: English
15th June 2023
Justyna Gołębiewska (AOI AMU)
Students’ presentations show concepts and feasibility studies of a space mission to a selected Solar System object. The mission concepts were prepared as part of the “Astronomy of the Solar System” lectured by dr. Justyna Gołębiewska using the Problem-based learning method.
Language: Polish
1st June 2023
Tadeusz Jopek (AOI AMU)
The Shower Database (SD) of the Meteor Data Center (MDC) had been operating on the basis of stream-naming rules which were too complex and insufficiently precise for 15 years. With a gradual increase in the number of discovered meteor showers, the procedure for submitting new showers to the database and naming them led to situations that were inconsistent with the fundamental role of the SD — the disambiguation of stream names in the scientific literature. Our aim was to simplify the meteor shower nomenclature rules. We proposed a much simpler set of meteor shower nomenclature rules, based on a two-stage approach, similar to those used in the case of asteroids. The first stage applies to a new shower just after its discovery. The second stage concerns a repeatedly observed shower, the existence of which no longer raises any doubts. Our proposed new procedure was approved by a vote of the commission F1 of the IAU in July 2022.
Language: Polish
8th June 2023
National holiday
25th May 2023
dr Grzegorz Nowak (Instituto de Astrofísica de Canarias and Universidad de La Laguna and Nicolaus Copernicus University)
The basic characterisation of planets (internal structure, formation history and possible atmospheric composition) starts with a measurement of their masses and radii. The need to know both of these quantities is a motivation for a great development of the ground- and space-based transit surveys and for a continuous importance of the radial velocity (RV) technique, which together became a tandem of mutually supporting observing techniques. Having the three main planetary quantities, i.e. mass, radius and mean density, we are in a position to study the planets’ internal structure as well as their formation and evolution, by placing them within mass-radius and mass-density diagrams. Precise RV measurements from 3-4-metre class telescopes are fundamental in determining planetary masses, in filling these diagrams, and in explaining the large scatter in fundamental properties, especially for the smallest planets of 1-4 Earth radii.
In this talk I am going to present recent results of radial velocity follow-up of Kepler-K2 and TESS planet candidates with TNG/HARPS-N and CAHA/CARMENES instruments in a framework of KESPRINT and CARMENES consortia. These results include sub-Neptune planets around nearby M dwarfs LTT 3780 (TOI-732) and G 9-40 (K2-313, TOI-5097), an ultra-short-period, 1.7 R_Earth planet around a solar-type star HD 20329 (TOI-4524), sub-Saturn around G7V star K2-280, and a planetary system around G9V star HD 191939 (TOI-1339), including HD 191939 g – Uranus-mass planet in the habitable zone with an orbital period of ~300 days.
Language: English
18th May 2023
Martin Solar (AOI AMU)
Core-collapse supernova (SN) explosions mark deaths of massive stars. They are responsible for the production of heavy elements and for the energetic feedback halting star formation, that have a profound impact on galaxy evolution.
Details of these processes depend on the stellar progenitors of a given SN type, however, the progenitors of Type Ic SNe (without hydrogen and helium lines in their spectra) have not been confirmed in pre-explosion images and it is unclear if they originate from the core-collapse of very massive stars (> 30 M⊙) or from less massive stars in binary systems (10 − 20 M⊙).
In this walk I will show that Type II and Type Ic SNe are located in environments with similar molecular gas densities, showing that their progenitors have comparable lifetimes and therefore similar initial masses (2σ range of 10–13 M⊙ for Type Ic SN progenitors, assuming an initial mass of Type II SN progenitors of 11 M⊙).
Our finding supports binary models for most Type Ic SNe, arguing that the lack of hydrogen and helium in their spectra is due to the interaction with a companion star, responsible for stripping the outer layers. This can be used to compute the SN metal production, and be implemented in sub-grid processes in order to improve SN feedback and chemical mixing in numerical cosmological simulations.
Language: English
11st May 2023
Dagmara Oszkiewicz (AOI AMU)
The early Solar System was populated with numerous differentiated (into iron core, silicate mantle and crust) planetesimals. These objects evolved and grew into planets. Some were destroyed in collisions. Crust fragments of those bodies can still be observed in the main asteroid belt as basaltic V-type asteroids. In this project we have determined spins and shapes of V-type asteroids with the aim to reconcile them with numerical simulations of Nesvorny et al. 2008 and the planetesimal formation theory of Bottke et al. 2006.
Language: English
20th April 2023
Krzysztof Kamiński (AOI AMU)
The time scale characterising the vast majority of observed astronomical phenomena is many orders of magnitude larger than one second. However, in the case of asteroid occultations and especially in the case of the astrometry of artificial, low-Earth orbit satellites, the required accuracy is much greater, up to 0.1 millisecond. Such accuracy is difficult to achieve and verify. Therefore, in recent years, several devices specifically designed for testing the absolute timing accuracy of a camera have been developed. The findings obtained with the newest camera test device shall be presented.
Language: English
13rd April 2023
Agata Rożek (University of Edinburg, Scotland)
On 26th September 2022 NASA conducted the first asteroid deflection test using the DART spacecraft. The probe hit a small moon Dimorphos orbiting a near-Earth asteroid Didymos. One of the principal mission aims was to change orbital period of Dimorphos in the asteroid system in a measurable way, and it was a smashing success. The collision aftermath was closely monitored from space and ground, including by the observers from Edinburgh’s Institute for Astronomy. We used the Danish 1.54m telescope in Chile, the VLT, and a brand-new telescope in Kenya. The global observing campaign was designed for determining the period change and monitoring post-impact ejecta. The orbital change was measured to be -33±1 min, and confirmed with two different observational methods: the optical observations and Doppler-delay radar imaging. I’ll present an overview of the DART mission and Edinburgh’s contribution to the Didymos/Dimorphos observing campaign.
Language: English
16th March 2023
Mark Trueblood (Winer Observatory, Arizona)
Introduction to the Winer Observatory
Language: English
9th March 2023
Tomasz Kwiatkowski (AOI AMU)
Language: English
2nd March 2023
Organizational matters
Language: Polish
2nd February 2023
Organizational matters
Language: Polish
26th January 2023
Karolina Dziadura (AOI AMU UAM)
We determine the non-gravitational transverse acceleration (the Yarkovsky effect – A2) using Gaia DR3 asteroid astrometry for 446 Near Earth Asteroids including 93 Potentially Hazardous Asteroids and 54 094 IMBA and Mars Crossing asteroids. For orbit determination, we used OrbFit software and the differential correction method. The software has been subject to years of testing and validation and is currently being used by the European Space Agency. We used all data available in Minor Planet Centre (MPC), all radar data and all Gaia DR3 observations and a new, more complex weighing scheme for asteroid astrometry. Thanks to Gaia DR3 and the new weighing scheme we improved the orbit uncertainties and detected the reliable A2 value for 60 Near Earth Asteroids, including 25 new detections and 35 improvements in signal-to-noise ratio. By adding a relatively small amount of ultra-precise astrometry from Gaia DR3 we significantly improved the orbit parameters for studied objects.
Language: English
19th January 2023
Regina Rudawska (ESA)
Since Jan 2009, European Space Agency (ESA) has a so-called ’Space Situational Awareness’ programme, addressing, among other points, the topic of Planetary Defence. Planetary Defence means to ensure that we know about asteroids potentially hitting our planet, and what to do about it. In my talk I will present the overview and the main tasks of Planetary Defence Office (PDO). More at the technical portal
http://neo.ssa.esa.int, focusing on providing information on the scientific and technical community.
Language: English
12nd January 2023
Oleksyi Golubov (AOI AMU and Kharazin University, Kharkiv, Ukraine)
I’ll review the influence of the radiation pressure forces on the dynamics and evolution of asteroids, the so-called Yarkovsky and YORP effects. Special attention will be devoted to the theoretical description of these effects, their significance for the evolution of asteroids, and my own results: the tangential YORP effect and possible dynamic equilibria for asteroids subject to YORP.
Language: English
5th January 2023
Dagmara Oszkiewicz (AOI AMU UAM)
In this work, we performed spectral analysis of V-type asteroids observed by the Gaia mission. Data Release 3 increases the sample size of known V-types by more than three times as compared to the literature. Using the data provided by Gaia we identified ~2000 plausible V-type asteroids. About 350 of them successfully pass our data validation criteria. We determined spectral parameters of the best sample. We confirm that the V-type asteroids in the middle and outer part of the main belt show distinct spectral properties compared to typical vestoids. In the inner main belt, we found a great diversity of spectral parameters among the V-types in all populations. Number of asteroids show band depths even greater than that of (1459) Magnya. Furthermore, some objects present 0.9~\mu m band-centers more than one standard deviation away from the typical value for vestoids. Overall our results indicate that the inner main belt may contain remnants of multiple differentiated planetesimals, not just (4) Vesta.
Language: English
22nd December 2022
Oleksyi Golubov (AOI AMU and Kharazin University, Kharkiv, Ukraine)
Language: English
Seminar has been cancelled
15th December 2022
Jarosław Włodarczyk Institute for the History of Science, Polish Academy of Sciences, Warsaw
In this paper I intend to discuss the astronomical content of a set of 22 letters written in the years 1648–1654 and exchanged by Johannes Hevelius (1611–1687) with Maria Cunitia (1610–1664) and her husband, Elias von Löwen (Crätschmair, c. 1602–1661), a couple based in Silesia. Maria Cunitia is acknowledged for her Urania Propitia (1650), an innovative adaptation of the mathematical astronomy of Johannes Kepler’s Rudolphine Tables (1627). In turn von Löwen authored astronomical calendars and ephemerids.The letters can be seen as an extraordinary example of the exchange of thoughts involving, on the one hand, a representatives of the mainstream European astronomy of the 17th century (Hevelius) based in an acknowledged scientific center (Gdańsk) and, on the other, astronomers working in the periphery of then scientific Europe. The correspondence features several significant astronomical themes, which cast new light on the activities of astronomers in the first half of the 17th century, and even on the chronology of discoveries. These include telescopic observations of the positions of the planets made to verify the accuracy of astronomical tables, studies of the optical libration of the Moon in the period preceding Galileo Galilei and Hevelius, and discussion of the usefulness of various observational tools such as the telescope.
Language: English
8th December 2022
Anne-Charlotte Perlbarg (Observatoire de Paris)
Potentially Hazardous Asteroids (PHAs) are small bodies making very close encounters with the Earth. PHAs are a real danger and depending on their size, an impact may have catastrophic consequences. The knowledge of their dynamics is essential for the purpose of an international program of planetary defense. Thus, accurate astrometric measurements acquired over a large time span are important to provide reliable orbits and impact probability, which often need to take into account accelerations such as Yarkovsky effect. Photographic plates made during the 19th and 20th century consist of a substantial source of old observations of Solar System objects. From existing databases, we have identified precovery observations of PHAs: i.e. fortuitous observations made before its discovery. We used the NAROO machine to digitize the plates and realized the astrometric reduction with Gaia eDR3 reference star catalog. Metadata have been verified and corrected through the measurement of the position of Main Belt Asteroids in the field of view. We added the results to observation dataset of PHAs to define new orbital solutions and detect Yarkovsky effect with the NIMA software. It shows an improvement of the accuracy of their new ephemeris depending on the asteroid. Our analysis demonstrates the interest of using precovery observations from photographic plates. It allows us to better assess the risk and impact probability of PHAs in the context of Planetary Defense or Space Situational Awareness.
Language: English
1st December 2022
Wojciech Dimitrow (AOI AMU UAM)
The application of the Wilson-Devinney method to model star-planet pairs will be presented. The possibility of studying fainter effects such as reflected light, ellipsoidal variations, and spots on the surface of the parent star will be discussed. In addition, an overview of recent results in the study of exoplanets will be presented.
Language: English
24th November 2022
David Vokrouhlicky (Charles University, Prague)
Asteroid families are groups of asteroids that share similar heliocentric orbits. They result from a collision between a parent object of the family and sufficiently large projectile; what we see now are fragments from this event. As such, data about asteroids in families can offer a unique probe of the fragmentation process and interior properties of the parent body. In this talk I will focus on yet another aspect, namely on our ability to determine epoch when in the past the family formed (thence the age of the family). Hunt for very young families have led not only to new methods of discovering families themselves, but also an entirely new population of asteroid pairs. Unlike families, the pairs are predominantly formed by rotational fission of the parent body, and represent siblings to asteroid binaries. I will finish my talk with discovery of a stunningly young pair.
Language: English
17th November 2022
Yurij Krugly (IOA and Kharazin University, Kharkiv, Ukraine)
The investigation of physical properties of NEAs through systematic CCD observations has been carried out at the Institute of Astronomy of V.N. Karazin Kharkiv National University since 1995. It includes obtaining the rotation parameters, sizes and shapes of NEAs with an increased interest in the study of newly discovered and potentially hazardous objects. The observations are carried out within the framework of wide international cooperation.
In the presentation, I will focus on various aspects and results of these photometric and polarimetric observations:
(1) Discovery and study of binary NEAs;
(2) Observational confirmation of YORP and BYORP;
(3) Estimation of albedo and composition type by polarimetric observations.
Language: English
10th November 2022
Jakub Tokarek (AOI AMU)
Astronomical Observatory in Poznań started its work simultaneously with the foundation of the Poznań University (Uniwersytet Poznański) in the 1919. In the past one hundred years it had seven principals and dozens of rank-and-file employees. Their work laid the foundations for the current fields of research at the Observatory. In this talk I will try to depict the short profiles of some of these employees.
Language: English
3rd November 2022
Milagros Colazo (Universidad Nacional de Córdoba, Argentina)
We all know that the brightness of asteroids varies due to different factors. We can see this brightness variation in the Light Curves (magnitude variation due to the asteroid’s rotation about its axis) and the Phase Curves (magnitude variation as the asteroid moves in its orbit around the Sun).
Together with the “Grupo de Observadores de Rotaciones de Asteroides” (GORA), we measure the light curves of dozens of asteroids to obtain the periods and amplitudes of these objects. GORA is an international network of amateur astronomers with whom we publish all our measurements in the Minor Planet Bulletin (MPB).
A significant aspect of my Ph.D. work is to take advantage of the large amount of photometric data provided by the current large astronomical surveys. Using the Gaia sample, we have obtained a catalog of H and G parameters for 9817 asteroids. From this work, “Pyedra” was developed: a software package written in Python that allows fitting different phase curve models to large catalogs of observations. On the other hand, we performed a taxonomic classification of asteroids using the 5 Sloan filters.
It is crucial to prepare statistical and computational tools capable of taking full advantage of the big data revolution on asteroids.
Language: English
20th October 2022
prof. Michał Michałowski (AOI AMU)
During this interactive presentation I will discuss with the participants several key properties of gravitational lensing in the context of testing the general relativity theory. I will also discuss in which configurations we should expect lensing. Then I will present what properties of future telescopes (with >15 meter mirrors) are needed to detect stars lensed by the supermassive black hole in the centre of the Milky Way.
Language: English
13rd October 2022
Łukasz Tychoniec (ESO Garching)
In this talk I will present highlights of first three months since JWST started science operations. Aside from the news-making discoveries, I will present some of our first results of the JOYS collaboration (JWST Observations of Young protoStars). In addition I will put special focus on the exploration of the Solar System with JWST and what it has to offer in studies of small Solar System bodies.
Language: English
6th October 2022
Language: Polish
Previous talks in 2021/2022:
9th June 2022
Magdalena Otulakowska-Hypka (AOI AMU)
Two of only four known symbiotic recurrent novae erupted recently. These very rare events were monitored for the first time by the second-generation instruments at VLTI. Thanks to the ESO DDT channel we were able to react fast and collect VLTI data starting only a few days since the ignitions of both eruptions. We used all three VLTI instruments: PIONIER, GRAVITY, and MATISSE and resolved both objects spatially and spectroscopically. Our observations show complex structures and asymmetries which we model at milliarcseconds scale.
Language: English
2nd June 2022
Antoine Choukroun (AOI AMU)
With the high quantity of asteroids already discovered and according to techniques used in this field, scientists need a lot of data to characterise them. Today’s data on asteroids is mainly photometry on unresolved targets. It is easy to perform with small telescopes available even to amateur astronomers, with growing degree of automatisation. According to this, huge amounts of quality data are relatively easy to produce. Difficulty for scientist now is to reliably process this amount of data. Some already existing software solutions can be used with simple tools like aperture photometry, but they are not well suited for asteroid tracking or variable seeing conditions. If asteroids are moving fast or if there are some star passages brighter than the asteroid, these apertures could lose the target. It takes a lot of time to monitor algorithms, and finally it is not possible to process much data this way. On the other hand, some attempts to automatise the process have already been developed, but without convincing results.
We present a set of new python packages which automatise asteroid detection and lightcurve production. Also some other features have been already added to this package to help scientists with data analysing like asteroid(s) detection, flexible aperture size, star passage detection, data binning etc. To evaluate it we compared it with scripts based on STARLINK packages, which were extensively used in the past. Results are very similar, and in each tested case the package was in agreement with the results produced with STARLINK.
Language: English
26th May 2022
Tadeusz Michałowski (AOI AMU)
Abstract intentionally missing.
Language: Polish
19th May 2022
Jakub Tokarek (AOI AMU)
The talk will be based on the doctoral dissertation, which will concern the modelling and refinement of eclipsing binary star models, in particular those located in hierarchical systems. Binary and multiple systems make up the majority of observed stars. Since more than 50% of the stars in the vicinity of the Sun are multiple systems, we can assume that a similar situation occurs throughout the Galaxy. As Gaia provides us with new data on stars, a new method will be developed that allows determination of the probability of physical bonding of two visual components of a system. This method will then be used to discover new hierarchical systems. In addition, it is planned to study the statistical relationship between the physical characteristics of close binary systems and companion stars that are in wide orbits and to use the Wilson-Devinney method implemented in the PHOEBE project to accurately model several eclipsing systems to understand the parameters of the system. Data will come from the PST1 telescope observations (archival and future) and the Gaia space mission.
Language: English
12nd May 2022
Josef Ďurech (Charles University, Prague, Czech Republic)
Photometric observations of asteroids can be used for the reconstruction of asteroids’ shapes and rotations states. So far, the technique of lightcurve inversion has led to convex shape models of several thousand asteroids. I will briefly review the main principles of the lightcurve inversion, discuss its results – the distribution of asteroid spin axes in the main belt and collisional families, and show some “non-standard” cases – changing rotation period due to the YORP effect, non-principal axis rotation, and others.
Language: English
5th May 2022
Organizational matters
Language: Polish
28th April 2022
Joanna Drążkowska (LMU Munich, University Observatory)
Questions about the origins of Earth have forever accompanied humans. The classical theory of planet formation, established when the Solar System was the only one we knew, has been recently challenged and is undergoing major changes. In this talk, I will explain how the growing population of planets orbiting stars other than the Sun triggered the revision of this classical theory and outline the new, emerging theory of planet formation. I will pay special attention to the early stages of planet formation when dust grains grow to pebbles and the first gravitationally bound building blocks of planets, the planetesimals, form.
Language: English
21st April 2022
Leonid Shakun (Odessa National University, Ukraine)
Brief information on the structure of Ukrainian optical tracking networks for the observation of artificial satellites will be presented. I will analyze the measurement precision of the network’s telescopes based on observations of reference objects in 2021. Then, using the Ajisai satellite as an example, I will estimate the accuracy of the prediction of the satellite position as a result of processing the network observations. In the second part of the talk, the opportunities for fast photometric observations at the Odessa Observatory will be presented. I will show the results of our determination of the spin period, spin axis nutation period, and its oscillation amplitude of the Ajisai satellite.
Language: English
7th April 2022
Paweł Kankiewicz (Uniwersytet Jana Kochanowskiego w Kielcach)
Since the first asteroid was discovered in retrograde orbit (1999), various hypotheses have been formulated related to the physical characteristics and formation of this type of objects. The physical and orbital similarity to comets suggest an origin from their hypothetical reservoir: The Oort Cloud. More recent hypotheses, in turn, do not exclude an interplanetary origin. The presented research and its results are the results of a project that comprehensively investigated the dynamics of bodies in retrograde orbits and verified scenarios of their orbital evolution. Methods were worked out to study their long-term evolution, and to determine how long they live and remain in stable orbits in our planetary system. It was also verified in statistical terms how plausible is the scenario of inversion of such orbits due to perturbations. A possible influence of non-gravitational effects on the results was also investigated.
Language: Polish
31st March 2022
Aleksandra Leśniewska (AOI AMU)
Dust is a key component of the interstellar medium. The mechanism of dust removal from galaxies has not been completely understood yet. However, dust evolution is not only relevant in the context of interstellar medium, but is also one of the main factors defining the evolution of stars and the entire host galaxy. We will address this issue by the analysis of several thousand dusty galaxies, which are becoming passive. They are elliptical galaxies in which star formation has a much lower rate than what their masses could imply, yet an unnaturally large amount of dust is observed – comparable to the amount of dust in spirals. Recent years have brought a large amount of new observational data containing information about dust emissions in low-redshift galaxies, such as one of the major cosmological and galaxy evolution observation projects, Galaxy And Mass Assembly (GAMA). The analysis is conducted on a Herschel Space Observatory sample that differs from previous work not only in the number of objects, but most of all in a wider range of parameters. This allows the determination of how galaxies get rid of dust and the testing of the mechanism which is responsible for this.
Language: English
24th March 2022
Dorota Skowron (OA UW)
The Milky Way is a spiral galaxy. This is inferred from various methods, such as radio observations of Galactic gas, star counts, as well as from our extrapolation of structures seen in other galaxies. However, these methods are indirect and rely on many assumptions. Precise mapping of the Milky Way is also difficult because we may only observe it from the inside through clouds of gas and dust. In result, the exact picture of our Galaxy is still under debate.
However, distances can be accurately measured to Classical Cepheids, which are young pulsating variable stars. I will present a new comprehensive picture of our Galaxy in three-dimensions based on the positions in the sky and precisely measured distances of thousands of these objects.
Language: English
17th March 2022
Toni Santana-Ros (Univ. de Barcelona/Univ. de Alicante)
Almost every day, we point our telescopes at recently discovered Near-Earth Objects (NEOs) with the aim of enhancing their –still– preliminary orbit. The large majority of these discoveries are coming from the major surveys in this field, such as Pan-STARRS, the Catalina Sky Survey or ATLAS.
The story of 2020 XL5 began in December 2020, when it was detected by the Pan-STARRS1 survey at Haleakalāa Observatory in Hawaii. Observations followed during the next few days, and some of the preliminary orbit determinations pointed out the possibility that the object could be librating around the 4th Lagrangian point of the Sun-Earth system. This would make it the second known Earth Trojan asteroid! But the confirmation of this discovery wasn’t a bed of roses…
In this talk, we will learn about the story of a group of brave astronomers who defeat all the villains in their way to discover the second Earth Trojan asteroid.
Language: English
10th March 2022
Edyta Podlewska-Gaca, Krzysztof Langner (AOI AMU)
In the talk we are going to present the Europlanet-2024-Research Infrastructure project. In the framework of the H2020 programme AOI in collaboration with over 50 international institutions realize world wide project aiming in developping the whole planetary science and strengtening the communication with the community.
We will present main goals of the project and the alert system which we are developping in our Observatory.
Language: Polish
3rd March 2022
Joachim Krüger (AOI AMU)
In this talk, I will introduce the problem of determining the atmospheric parameters and present results obtained during my master’s thesis. Atmospheric parameters, i.e., effective temperature, surface gravity, metallicity, micro- and macroturbulence, and detailed chemical composition, describe the state of the stellar atmosphere. Their determination is the first step in a specific stellar analysis.
In my work, I calculated the atmospheric parameters for selected 45 stars of A- and F- types observed in the Kepler field. For the spectral analysis, I used high-resolution spectroscopic data from the ESPaDONS spectrograph (CFHT 3.6-m). The atmospheric parameters and rotational velocities were calculated using the iSpec code with spectrum synthesis technique.
I will also briefly introduce further and future works for the presented sample of stars at the end of the talk.
Language: English
24th February 2022
Jakub Nadolny (AOI AMU)
In this talk, I will focus on the molecular gas content of star-forming galaxies. The selection process was based on the presence of gamma-ray bursts (GRBs), and the availability of IR- or radio-based star formation rates (SFRs). A total of four galaxies were selected. Using observations (PI: M. Michałowski) of atomic carbon [CI](1-0) emission, we were able to estimate an upper limit of [CI](1-0) line luminosities. Using three different methods we converted luminosities into the molecular gas mass for our GRB host galaxies.
A compilation of star-forming galaxies with [CI](1-0) fluxes is used to compare our findings. As a preliminary result, we find a molecular gas deficiency for galaxies with robust measurements. Furthermore, comparing the molecular masses estimated based on CO, we find that [CI]-based masses are lower by about ~1.3 dex. Since the [CI] atomic gas has been shown to trace the bulk of the molecular gas, we argue that the discrepancy of the results is due to the overestimated conversion factor (alpha_CO) used in previous work. Furthermore, since the GRBs are preferentially found in the metal-poor galaxies (i.e. below solar metallicity), we argue that due to the mass-metallicity relation, the most massive (i.e. log(M*) > 10) galaxies need to lower the metal content for example via metal-poor gas inflow, or a minor merger with the metal-poor galaxy in recent past.
In the second part of the talk I will comment on my PhD investigation within the OTELO survey (if I have some time left).
Language: English
27th January 2022
Ewa Śreniawska (AOI AMU)
Delta Ceti is one of the longest studied pulsating variable stars of the beta Cephei type. The first observational data back to the first years of the 20
th century. In the mid-1960s, a change in period was observed. Subsequent research confirmed this, and most astronomers preferred a model with a constant rate of change in the pulsation period, the origin of which was found in the evolution of the star. However, the results of the research conducted so far have not allowed to obtain a coherent and unambiguous explanation of the observed changes.
In the years 2014-2018, a spectroscopic campaign was carried out with the use of GATS (Global Astrophysical Telescope System) telescopes which collected over a thousand high-resolution spectra of this object. Our observations are the largest homogeneous spectroscopic data set for this star.
The analysis of both historical and our observations data showed that the most probable cause of changes in the pulsation period is the presence of a second component with a minimum mass of 1.1 M_sun in an orbit with a period of about 169 years.
Language: Polish
20th January 2022
Anna Marciniak (AOI AMU)
Slowly rotating asteroids turn out to be abundant, yet little is known about their physical properties. In our wide campaign we observe them in a rich network of small telescopes (including amateur observatories), gathering lightcurves in the visible from multiple apparitions, for spin and shape reconstruction. In addition, we are using thermal data from infrared satellites. We join both types of data in one optimisation process for modelling their spins, shape, sizes and thermal properties.
Using the Convex Inversion Thermophysical Model we recently obtained detailed models for 16 slow rotators, with the slowest one having the rotation period of as long as 59 hours. Our thermal inertia determinations provide valuable input where previously have been very few objects. Still, we cannot confirm the trend for larger thermal inertia with longer period, that if present, would allow us to study deeper layers of their surfaces. We also scaled the targets in size by fitting the shape models silhouettes to stellar occultations timings, and obtained good agreement with sizes from thermal fitting.
Our study joins a wide approach: from amateur astronomers observations to data from space observatories, and from pure lightcurve inversion to a more sophisticated simultaneous optimisation with thermal data, for a comprehensive view of these interesting targets.
Language: English
13rd January 2022
Julia Pietrzak (AOI AMU)
The prediction close-approaches of satellite objects is one of the key issues of the SST program. The purpose of such activities is to protect satellites from collisions with space debris. However, in order to obtain correct results, the orbit must be well propagated. For this purpose, I use the Orekit library to create a program that allows me topredict the moments of close-ups, as well as the distances at which the objects will approach.
Language: Polish
16th December 2021
Krzysztof Hełminiak (CAMK PAN, Toruń)
The CREME project is a large spectroscopic survey aimed for a large number (~380) of detached eclipsing binaries (DEBs), supported by high-precision photometry, mainly from the space missions (TESS, Kepler/K2). The goal is to identify and characterise stars of rare or poorly studied classes by providing an extended set of orbital, physical, and atmospheric parameters derived with high precision. The sample contains variety of different objects (giants, low-mass stars, multiples, pulsators), many of which were studied for the first time. In my talk I will present some of the latest results, including models of targets from the TESS Guest Investigator programme, and mass estimates of 630 stars in 315 double-lined spectroscopic DEBs.
Language: English
9th December 2021
Alexey Sergeyev (Observatoire de la Côte d’Azur, Nice, France)
The populations of small bodies of the Solar System (asteroids, comets, and Kuiper Belt objects) are used to constrain the origin and evolution of the Solar System. Their orbital distribution and composition distribution are both required to track the dynamical pathway from their formation regions to their current locations. We aim to increase the sample of Solar System objects (SSOs) that have multifilter photometry and compositional taxonomy. To do this we searched for moving objects in the SkyMapper Southern Survey. We used the predicted SSO positions to extract photometry and astrometry from the SkyMapper frames. Then we applied a suite of filters to clean the catalog from false-positive detections and finally we used the near-simultaneous photometry to assign a taxonomic class to objects. We release a catalog of 880,528 individual observations, consisting of 205,515 known and unique SSOs. The catalog completeness is estimated to be about 97% down to V=18 mag and the purity is higher than 95% for known SSOs. The near-simultaneous photometry provides either three, two, or a single color that we use to classify 117,356 SSOs with a scheme consistent with the widely used Bus-DeMeo taxonomy.
Language: English
2nd December 2021
Anna Marciniak (AOI AMU)
Slowly rotating asteroids turn out to be abundant, yet little is known about their physical properties. In our wide campaign we observe them in a rich network of small telescopes (including amateur observatories), gathering lightcurves in the visible from multiple apparitions, for spin and shape reconstruction. In addition, we are using thermal data from infrared satellites. We join both types of data in one optimisation process for modelling their spins, shape, sizes and thermal properties.
Using the Convex Inversion Thermophysical Model we recently obtained detailed models for 16 slow rotators, with the slowest one having the rotation period of as long as 59 hours. Our thermal inertia determinations provide valuable input where previously have been very few objects. Still, we cannot confirm the trend for larger thermal inertia with longer period, that if present, would allow us to study deeper layers of their surfaces. We also scaled the targets in size by fitting the shape models silhouettes to stellar occultations timings, and obtained good agreement with sizes from thermal fitting.
Our study joins a wide approach: from amateur astronomers observations to data from space observatories, and from pure lightcurve inversion to a more sophisticated simultaneous optimisation with thermal data, for a comprehensive view of these interesting targets.
Language: English
The talk has been cancelled due to the COVID-19 related restrictions.
25th November 2021
Antti Penttilä (University of Helsinki, Finland)
We explore the performance of neural networks in automatically classifying asteroids into their taxonomic spectral classes. We particularly focus on what the methodology could offer the ESA Gaia mission. We constructed an asteroid dataset that can be limited to simulating Gaia samples. The samples were fed into a custom-designed neural network that learns how to predict the samples’ spectral classes and produces the success rate of the predictions. The performance of the neural network is also evaluated using three real preliminary Gaia asteroid spectra.
The overall results show that the neural network can identify taxonomic classes of asteroids in a robust manner. The success in classification is evaluated for spectra from the nominal 0.45–2.45 µm wavelength range used in the Bus-DeMeo taxonomy, and from a limited range of 0.45–1.05 µm following the joint wavelength range of Gaia observations and the Bus-DeMeo taxonomic system. The obtained results indicate that using neural networks to execute automated classification is an appealing solution for maintaining asteroid taxonomies, especially as the size of the available datasets grows larger with missions like Gaia.
Language: English
18th November 2021
Piotr A. Dybczyński (AOI AMU)
We obtain more and more precise data on the nearby stars, but still accurate parameters of close stellar approaches to the Solar System are difficult to obtain in many cases. As a result, estimating the effect of stellar perturbations on long-period comet motion is a complicated task and sometimes simply impossible now.
Language: Polish
4th November 2021
Jacek Haponiak (AOI AMU)
The Colombo top model describes rotational dynamics of a rigid body, moving around the material point, under the effect of gravitational interaction. Classical mechanics action-angle variables is a set of canonical variables, useful in solving many integrable systems. During presentation the action-angle variables for the Colombo top model will be shown.
Language: Polish
28th October 2021
Hanna Klimczak (AOI AMU, Politechnika Poznańska)
The aim of the project is the classification of asteroids according to the most commonly used asteroid taxonomy (Bus-Demeo et al. 2009) with the use of various machine learning methods like Logistic Regression, Naive Bayes, Support Vector Machines, Gradient Boosting and Multilayer Perceptrons. Different parameter sets are used for classification in order to compare the quality of prediction with limited amount of data, namely the difference in performance between using the 0.45mu to 2.45mu spectral range and multiple spectral features, as well as performing the Prinicpal Component Analysis to reduce the dimensions of the spectral data.
Language: English
21st October 2021
Volodymyr Troianskyi (AOI AMU)
The Lucy mission consists of five flybys of Trojan asteroids to investigate the differences in surface and internal properties across the population of Trojan asteroids. From these five encounters we will be able to observe seven Trojan asteroids: (3548) Eurybates and its small satellite Queta, (15094) Polymele, (11351) Leucus, (21900) Orus, (617) Patroclus, and Meneotius.
We make photometric observations of these targets to confirm the taxonomy of asteroids, rotational periods and creating phase curves.
Language: English
14th October 2021
Tomasz Kwiatkowski, Paweł Koleńczuk (AOI AMU)
Very Small Asteroids (objects with diameters smaller than about 150 m) can be spun-up by the YORP effect to rotation periods as short as tens of seconds. It is also hypothesised, that in the same process their spin axes are asymptotically drawn to the position perpendicular to the orbital plane. So far this effect has been observed only for one VSA and needs further verification. In this talk results of an observing campaign of 2021 DW1, shall be presented. During 6 days in March 2021 this object swept a 170 degrees long arc on the sky which made it an excellent target for physical characterisation, including spin axis and shape derivation.
Language: English
Previous talks in 2020/2021:
17th June 2021
Marco Micheli (NEO Coordination Centre, ESA)
ESA’s NEO Coordination Centre, established 8 years ago in Frascati,near Rome, is one of the components of ESA’s Planetary Defence Programme.
Among the tasks of the Programme and the Centre is the collection of astronomical observations of NEOs, with a specific focus on asteroids presenting a non-zero impact threat to our planet. The observational activities of the Programme are divided into various tasks. Among them are:
– The development of a dedicated NEO survey telescope, the so-called “Flyeye”, soon to be installed in Southern Italy, plus two other mixed-use wide-field telescopes in Spain and Chile.
– The collection of high-precision astrometric observations of possible impactors, with various facilities worldwide (including a dedicated program with ESO’s VLT).
– The establishment of a worldwide network of telescopes, with global latitudinal and longitudinal coverage, capable of ensuring quick-reaction observational capabilities in case of upcoming impact
threats (the so-called “imminent impactors”)
– The development of resources and capabilities for archival searches and precoveries.
In this talk we will discuss the importance of NEO observations for the mitigation of the asteroidal impact threats, and present some of the key observational results of our Programme.
10th June 2021
Tadeusz Jopek (AOI AMU)
In the first part of my speech, two approaches of generating synthetic orbits of small bodies will be presented.
Briefly, two methods will be presented:
1) based on the multivariate kernel density estimation (KDE) of the probability density function, and
2) using the cumulative probability distribution (CPD) inversion method.
In the second part, using the available sample of small body orbits, the properties of synthetic orbits obtained by each of the methods will be compared.
27th May 2021
Karolina Dziadura (AOI AMU)
The orbital motion of small bodies is affected by the Yarkovsky effect. First-time the effect was proposed by Yarkovsky in 1901 and then popularized by Öpik in the 1950s. However, the first direct detection was only made in 2003 thanks to radar observations. Nowadays there are over hundred detections for NEAs and only a few for Main-Belt objects.
The main goal of this study is to improve an asteroid orbit using GAIA DR2 astrometry. It was claimed that the Gaia mission will improve asteroids orbits and to find new Yarkovsky detections thanks to the high precision and accuracy of its astrometry. I converted all of the available data to ADES format and then used it to orbit determination. I used OrbFit software which is a Fortran program for orbit propagation, ephemerides computation, orbit determination, close approach analysis, and impact monitoring. I will show results for 42 asteroids, where for 21 of them I obtained an A2 parameter with signal to noise ratio greater than 3.
20th May 2021
Lukas Shrbeny (Czech Academy of Science)
This talk should provide brief introduction into observation of fireballs, their sources, and basic physical properties that can be determined from observations and modeling.
13rd May 2021
Michał Michałowski, Krzysztof Kamiński (AOI AMU)
Gamma-ray bursts (GRBs) are explosions of the most massive stars. The detection of even a single GRB exploding in the very early Universe is important because it allows us to constrain the star-formation activity and the conditions necessary for such stars to be formed. We will show that a recent extraordinary discovery of a GRB at a redshift of 11 (only 420 million years after the Big Bang) was in fact due to a signal from a man-made satellite BREEZE-M DEB (TANK), a debris from a Proton rocket.
6th May 2021
Emil Wilawer (AOI AMU)
The number of sparse asteroid photometry being gathered by both space and ground-based surveys is growing exponentially. This big volume of data poses a computational challenge both due to large amount of data to be processed as well as new methods needed to combine data from various sources (e.g. obtained by different techniques, in different filters, having different random and systematic errors). I will present a novel approach to obtain asteroid phase curves combing sparse Gaia DR2 photometry and differential ground-based photometry, that in the traditional approach cannot be used for phase-curves. Combining those two data types allows for extraction of phase-curve information for growing number of objects. The main goal is to develop algorithm capable of merging sparse and dense data sets both relative and differential in preparation for asteroid observations originating for example from the Gaia, TESS, ATLAS, LSST, K2, VISTA and many others.
29th April 2021
Volodymyr Troianskyi (AOI AMU)
Since July 2014, the ESA Gaia mission has been surveying the entire sky down to magnitude 20.7 in the visible. In addition to the millions of stars, thousands of Solar System Objects (SSOs) are observed daily. By comparing their positions to those of known objects, a daily processing pipeline filters known objects from potential discoveries. However, owing to Gaia’s specific scanning law designed for stars, potential newly discovered moving objects are characterized by very few observations, acquired over a limited time. This aspect was recognized early in the design of the Gaia data processing. A daily processing pipeline dedicated to these candidate discoveries was set up to release calls for observations to a network of ground-based telescopes. Their aim is to acquire follow-up astrometry and to characterize these objects. From the astrometry measured by Gaia, preliminary orbital solutions are determined, allowing to predict the position of these potentially new discovered objects in the sky accounting for the large parallax between Gaia and the Earth (separated by 0.01 au). A specific task within the Gaia Consortium has been responsible for the distribution of requests for follow-up observations of potential Gaia SSO discoveries. Since late 2016, these calls for observations (called alerts) are published daily via a Web interface, freely available to anyone world-wide. Between November 2016 and July 2020, over 1700 alerts have been published, leading to the successful recovery of more than 200 objects. Among those, six have provisional designation assigned with the Gaia observations, the others being previously known objects with poorly characterized orbits, precluding identification at the time of Gaia observations. There is a clear trend for objects with a high inclination to be unidentified, revealing a clear bias in the current census of SSOs against high inclination populations.
15th April 2021
Krzysztof Kamiński (AOI AMU)
Astronomical Observatory of Adam Mickiewicz University in consortium with the University of Zurich, ITTI company in Poznań and 6ROADS company in Kraków (consortium leader) carried out in 2019-2021 an European Space Agency project named SPACE STONES (Space Surveillance and Tracking in Observational Network with Event-based Sensors). In the course of this project we carried out laboratory and observational tests in order to assess the Dynamic Vision Sensors (DVS, also named Event Based Sensors, EBS) in satellite tracking and survey. We developed a methodology for accurate timing of camera events, software to convert data stream to FITS format and methods to observe an astrometrically analyze data from these cameras. We have made for the first time in history (to our knowledge) astrometric measurements of navigational satellites with a DVS camera, together with evaluation of its limiting magnitude, astrometric and timing accuracy.
8th April 2021
Irina Belskaya (Karazin Kharkiv National University)
Polarimetry is an effective remote sensing tool for studying surfaces of atmosphereless small Solar system bodies, in particular, for assessing surface albedo and texture. Last decade the interest to polarimetric investigations has been increased first of all thanks to the progress in instrumentation. The achievements and problems of using polarimetry for studying surfaces of atmosphereless small Solar system bodies from near-Earth asteroids to transneptunian objects will be discussed.
25th March 2021
Tomasz Kwiatkowski (AOI AMU)
SANORDA is an acronym for Service for Archival NEO Orbital and Rotational Data Analysis. It has been developed by our Institute under a contract from ESA. SANORDA is web based and consists of four modules: NHOD (for analysing the influence of the number of astrometric observations of newly discovered NEOs on the accuracy of the orbits computed for them), NLCD (for storing and visualising asteroid lightcurves), NPDT (for computing asteroid rotation periods from their lightcurves), and NPAT (for fitting phase functions to the asteroid magnitude-phase relations). In the talk, several use cases of SANORDA, which can be of interest to asteroid researchers, will be presented.
18th March 2021
Edyta Podlewska-Gaca (AOI AMU)
Dzisiejsze seminarium będzie o współpracy astronoma z lekarzem okulistą i o tym jak doszło do stworzenia klasyfikacji ostrego uszkodzenia plamki żółtej w wyniku patrzenia na słońce bez ochrony.
11st March 2021
Edyta Podlewska-Gaca (AOI AMU)
Kepler mission is powerful tool to study the different types ofastrophysical objects or events in the distant Universe. However, the spacecraft gives also the opportunity to study Solar System objects passing in the telescope field of view. In my talk I will present the results obtained from the K2C9 campaign, for which we have determined for the first time the rotation periods of a number of asteroids observed by the Kepler satellite, and I will show some interesting features displayed by studied objects.
11st February 2021
Steve Schulze (Stockholm University)
The paradigm shift from galaxy-selected to quasi-synoptic surveys led to a revolution in the study of optical transients. The Palomar Transient Factory (PTF) has played an important role in this revolution. PTF was a fully-automated, wide-field survey using the 1.2-m Samuel Oschin telescope (P48) at Palomar Observatory (USA). Between 2009 and 2017, PTF discovered almost 900 core-collapse supernovae. Here, I present the host galaxy properties of the core-collapse supernova sample. I obtained photometry from the rest-frame UV to the NIR for each host and modelled the spectral energy distributions to extract the mass and star-formation rate of each host. I will contrast each sub-class’s ensemble properties with expectations from field-galaxy samples to deduce whether different classes of core-collapse supernovae show a preference for particular galactic environments. Furthermore, I will show how we can use SNe as beacons to study extreme star-formation environments and how we can use them to select rare phases in galaxy evolution.
4th February 2021
Tadeusz Jopek (AOI AMU)
In the morning of 29 Jan 2021 at 6:04:54-58 UTC a bright bollide was seen from different locations in the Czech Republic and Poland. Due to a bad weather, no recordings from profesional meteor cameras are available. However, the event was registered by several citizen cameras, and the videos can be found on the internet. If a proper astrometric calibration is done, such videos can be used to compute the bolide’s trajectory.
There are two videos recorded from Poland. One video (from a standing car) has been taken from a site very close to Poznan. Another one, on which the end of the bolide trail is seen, has been recorded from a moving car close to Świebodzin, near Zielona Góra. Both videos are crucial in determination of the impact point of probable meteorites.
In a short talk I will discuss the method that can be used to calibrate both videos and ask for volunteres to do the job.
28th January 2021
Monika Kamińska (AOI AMU)
Growing population of man-made Earth-orbiting objects requires constant monitoring, which main goal is to predict possible collisions of functioning satellites with other objects. Monitoring of this type is usually done via one of two main techniques: radar or optical observations. Observing satellites with optical telescopes is challenging due to brightness diversity of observed objects (from very bright to very faint), their on-sky angular speeds reaching in extreme cases up to several degrees per second and other factors. During the talk an overview will be presented of the ongoing ESA project “OGS Camera Requirements and Benchmarking”, which includes modernization plan of the camera dedicated to observations of Earth satellites at ESA Optical Ground Station (OGS), Tenerife. In this project the consortium of AO AMU and the 6ROADS company carries out theoretical analyses and practical tests of modern, currently available digital astronomical cameras in order to select the most optimal replacement for the current CCD camera at OGS.
21st January 2021
Magdalena Polińska (AOI AMU)
Asteroids are rocky remnants from the time when the Solar System was formed. Studying small bodies we can learn more about the formation and evolution of our Planetary System. We already know 420 binary asteroids. There are several types of binary systems. A special case of binaries are the systems with two bodies having similar size and with the same rotational and orbital periods – which are called synchronous binary asteroids. Observing and modeling binary objects is one of a few possible ways to get information about the values of the masses and sizes of bodies and then we can calculate their densities. During talk I would like to present actual data and results for this interesting group of binaries asteroids.
14th January 2021
Michał Michałowski (AOI AMU)
The way galaxies stop forming new stars (quenching) is a key aspect of galaxy evolution. This is connected with removal of gas, the fuel of star formation. I will review what we know about the mechanism of the removal of interstellar medium (ISM) from galaxies and how fast this process is. I will then present an alternative way to study the ISM removal by selecting dusty early-type galaxies, for which the decrease of gas and dust can be tracked as a function of age. This led to the first direct measurement of the ISM removal timescale and to the conclusion that the cold ISM is likely removed by feedback from old stellar populations.
17th December 2020
Tomas Kohout (Helsinki University)
Shock induced changes in ordinary chondrite meteorites related to impacts or planetary collisions are known to be capable of altering their optical properties. Thus, one can hypothesize that a significant portion of the ordinary chondrite material may be hidden within the observed dark C/X asteroid population. The exact pressure-temperature conditions of the shock-induced darkening are not well constrained. Thus, we experimentally investigate the gradual changes in the chondrite material optical properties as a function of the shock pressure.
10th December 2020
Aleksandra Leśniewska (AOI AMU)
There exists two classes of gamma ray bursts (GRBs), which are distinguished by the duration of the prompt high-energy emission. Long GRBs, with durations larger than 2 s, are firmly associated with the explosions of massive stars, although in three instances, luminous supernovae (SNe) have not been detected, despite deep observations. The nature of these bursts is unclear. Our aim is to establish the properties of the interstellar medium (ISM) of the host galaxy of one of these events, GRB 111005A, in order to shed light on the nature of these peculiar objects. We used new HI line measurements and previously published optical integral field spectroscopy in order to analyze the environment in which the GRB was located. We studied the distribution of the host properties e.g. atomic gas mass, star formation rate (SFR), and kinematics.
3rd December 2020
Paweł Koleńczuk (AOI AMU)
In my presentation, I will present the results of observation and photometric analysis of a very small near-Earth asteroid 2020 UA. The object was observed on October 20, 2020 with the 0.7-m RBT telescope. The presented results will concern the physical properties of the asteroid such as: rotation period, absolute brightness, size and taxonomic type.
26th November 2020
Przemysław Bartczak (AOI AMU)
Last years have seen a growing use of computing clusters in the research conducted at our Institute. Some topics are not selected due to the limitations in the access to the professional computing systems. During the talk a BOINC platform, based on the volunteered computer resources resources, shall be presented.
19th November 2020
Anna Łosiak (University of Exeter, UK)
Recognising small terrestrial impact craters developed in unconsolidated materials is a problem (French and Koeberl 2010). In such cases, impact cratering indicators, established based on larger structures formed in consolidated materials, are not useful: there are no shatter-cones and the amount of shocked quartz produced during the impact is very small and spread out over a large area. For example, in the Morasko strewn field (the largest structure is ~100 m in diameter), the volume of sediment shocked above 5 GPa (required for producing planar deformation features in quartz) is negligible (Bronikowska et al. 2017); extensive hunt for shocked grains remained unsuccessful (personal communication: A. Muszynski, A. Losiak). Because of that the main (and in most cases the only) recognition criterium applied for the small impact craters in unconsolidated materials is recognition of the preserved meteorite fragments associated spatially with the crater.
During the the seminal I will present results of my research on this topic performed as part of my Marie Skłodowska Curie Individual Fellowship at the at the University of Exeter.
12nd November 2020
Krzysztof Kamiński (AOI AMU)
Daily observations of artificial Earth satellites
5th November 2020
Dagmara Oszkiewicz (AOI AMU)
Characterisation of the V-type asteroid population may help to comprehend the planetesimal formation and evolution. Asteroid phase-curves are known to relate to surface properties such as asteroid taxonomy, surface roughness, particle size distribution, albedo and many others, providing insight into surface properties of the V-types.
Gil-Hutton et al. (2017) showed that the basaltic asteroids display two distinct polarimetric behaviors, which they attributed to the regolith particle size, however mineralogical differences can not be excluded. Considering that phase-curve parameters relate to surface and regolith properties, they may verify those distinct behaviors.
We observed about 20 asteroids during around 250 nights (over 500 fragmental lightcurves) to obtain high quality phase curves. We fitted the standard H,G; H,G1,G2, and H, G12 phase functions, limiting them to physical solutions only. This greatly extends the sample of well determined phase-curves for the underrepresented V-types. For asteroids with data from multiple oppositions we used a simultaneous fit assuming the same slope parameters in all apparitions and different absolute magnitude values. From these data we also derived the G12* parameter to be used in single parameter phase functions recommended for fitting low quality photometry. We do not find substantial evidence for any clustering into distinct phase curve parameters groups as suggested by Gil-Hutton et al. 2017. Only one asteroid (2763 Jeans) shows an exceptionally high G2 value.
Further work should be conducted to determine slope parameters of more V-types to further verify the division of V-type asteroids into two distinct groups. Obtaining phase curves of non-Vestoids (such as those in the mid and outer Main Belt) may also help clarify if the division into distinct V-type groups is due to particle size or mineralogical differences.
29th October 2020
Piotr A. Dybczyński (AOI AMU)
In numerical integration of long period comet motion aiming at their past and future dynamics studies over the previous or next orbital period it is necessary to take into account both Galactic and nearby stars perturbations. Now, after Gaia second data release we have roughly 650 such stars. If we want to include all mutual gravitational interactions such a calculations will become highly demanding. Moreover, having the equations of motion formulated in a Galactocentric frame we encounter serious numerical lost of precision when a comet moves in the solar vicinity. In this talk we show how one can overcome these difficulties.
22nd October 2020
Łukasz Wyrzykowski (OA UW)
Black holes (BH) are everywhere, there should be hundreds of millions of stellar-origin black holes in our Milky Way Galaxy. However, we only know about 50 or so cases, mostly from X-ray binaries, where a BH accretes matter from its stellar companion, or from binary system involving a star and a BH. Single black holes, even if nearby, are essentially black and invisible.
Gravitational microlensing offers an opportunity to discover black hole and other dark objects just by the fact they are massive and bend the background light. There have been thousands of microlensing events discovered by OGLE, Gaia, ZTF and other projects. However, in order to uniquely recognise a black hole lens and distinguish from a regular stellar lens, it is required to measure the size of the Einstein Radius as well as the distances of both lens and the source. Gaia space mission’s astrometric data will allow measuring Einstein radii for all events, however, without a dense photometric coverage of their light curves, the parallax effect willnot be measurable.
The Time-Domain work package of the EC’s Horizon 2020 OPTICON grant has been established in order to coordinate global long-term time-domain observations, such as of candidates for lensing black holes. In years 2021-2024, these actions will be extended also to radio time-domain observations, within the new Horizon 2020 grant OPTICON-RadioNET PILOT (ORP). In my talk, I will describe the current state of the black hole microlensing searches and will present the results obtained so far with the OPTICON Time-domain telescope network.
15th October 2020
Jakub Tokarek (AOI AMU)
In the building of the Astronomical Observatory in Poznań there is a difficult to count amount of all kinds of documents and historical materials. Some of them are older than the University of Poznań itself (founded in 1919). In the last few months, I managed to collect and organize materials from the period of the Second World War, when “Universitäts – Sternwarte Posen” was operating. The archive catalog currently has over 650 items, ranging from small bills, through correspondence of the Observatory’s employees, to annual reports. All of them, to a different extent, broaden the knowledge not only about the functioning of the Observatory, but also about the entire “Reichsuniversität Posen”, cooperation with other science centers in Europe, and even provide insight into the daily functioning of various parts of the Nazi Third Reich.
Talks in 2019/2020:
25th June 2020
Krzysztof Kamiński, Monika Kamińska (IOA)
Recently observed growth of the number of artificial satellites and space debris became an increasing complication to astronomical observations. Several authors have published their analysis of that problem, raising questions about the future of astronomical observations, especially for large field of view surveys and long exposure images. In order to address that issue we created a completely new web based service designed specifically to predict satellite passes and estimate their brightness in a selected sky region.
This is the first publicly available tool that can estimate SNR of a satellite trail for all satellites with publicly available orbits. We present the background methodology and real world tests with observations from several telescopes.
18th June 2020
Karolina Dziadura (IOA)
The orbital motion of small bodies is affected by the Yarkovsky effect. First-time the effect was proposed by Yarkovsky in 1901 and then popularized by Öpik in 1950s. However, the first direct detection was only made in 2003 using radar observations. Nowadays there are hundreds of detections for NEAs and only a few for Main-Belt objects. In this work, I attempt to detect the Yarkovsky effect among multiple Main-Belt objects and other asteroids. I will show preliminary results for five asteroids using the OrbFit software. OrbFit is a Fortran program for orbit propagation, ephemerides computation, orbit determination, close approach analysis, and impact monitoring. Orbits were calculated using FitObs with and without the Yarkovsky effect. Next, the ephemeris were computed for the times of GAIA observations and compared with the GAIA DR2 data.
4th June 2020
Julia Matysiak (IOA)
“Orekit” is a numerical library containing procedures that allow performing orbital calculations mainly in terms of the dynamics of artificial Earth satellites. It is used by many organizations such as CNES (Center National d’Études Spatiales), ESA (European Space Agency), and the U.S. Naval Research Laboratory. Every year more and more people start their adventure using “Orekit” for scientific purposes. Trying to use the library for orbital calculations, I try to answer questions about the potential of this library and for what purposes it can be used.
28th May 2020
Wojciech Dimitrow (IOA)
The V2080 Cyg system is an eclipsing pair of stars. Previous studies of other teams indicate that the stars are of similar masses and sizes, and that a trace of a third component is present in the object’s spectra. An observation campaign for V2080 Cyg was organized at our Observatory. Spectroscopic data was collected on two instruments. First one is the 1.88m Cassegrain telescope of the David Dunlap Observatory. The second instrument is PST1 equipped with an Echelle spectrograph. A large number of observations of very good quality allowed for accurate determination of mases of the eclipsing components. Additionally, the proper motions and parallaxes from the GAIA DR2 mission were analyzed. They indicate that the visual companions of the object are background stars which are not connected dynamically with the system.
21st May 2020
Przemysław Bartczak (IOA)
I will present the adaptation of the SAGE method enabling modeling of physical parameters of asteroids based on photometric observations and data from adaptive optics.
14th May 2020
Ewa Śreniawska (IOA)
Delta Ceti is one of the brightest and longest studied pulsating variable stars of the beta Cephei type. The beginnings of observation dates back to the first years of the 20th century. The star showed a systematic increase in the period of main pulsation. However, further data undermined this result, showing that the growing trend began to break down. There is also a hypothesis about the multi-modality of delta Ceti. The analysis to date has focused mainly on photometric observations, while spectroscopic observations were of poor quality. In the years 2014-2018 a spectroscopic campaign was carried out with the use of GATS (Global Astrophysical Telescope System) telescopes. 1022 high-resolution spectra were collected, which constitute the largest homogeneous spectroscopic data set for this star. The analysis showed that changes in the pulsation period are more complex than previously indicated. Also, no additional pulsation modes could be found. The obtained results allow us to hypothesize that such complicated variability may result from the presence of one or more invisible objects orbiting the star.
Sławomir Breiter (IOA)
Minor bodies rotation is affected by the YORP effect and inelastic deformations energy dissipation. According to the theoretical model (S. Breiter and M. Murawiecka), the YORP excites wobbling stronger than the energy dissipation damps it. And this contradicts the observed statistics.
30th April 2020
Magda Butkiewicz-Bąk (IOA)
According to the solar system’s theory of evolution, asteroids are the remnants of the formation of its internal regions. The main asteroid belt, Kuiper belt and dust are present in the Solar System and they are analogous to distant extrasolar systems, in which the so-called debris disks. Those objects can bring information about processes that took place in the protoplanetary disk and their evolution. Asteroids play an important role in that process. In my presentation I will present the results of the Very Small Asteroids research which were obtained during my PhD.
23rd April 2020
Anna Marciniak (IOA)
Observing occultation events is a very effective method to study small solar system objects. It allows determination of asteroid sizes, shapes, but also discovery of their satellites and even rings. For large transneptunian objects this technique also enables to determine their densities.
This observing technique is relatively simple – one just determines timing of two events: star disappearance and reappearance behind the occulting body. However, it is essential to conduct these observations in coordinated multi-site campaigns. Resulting multiple occultation chords increase the precision of derived parameters. The talk will present recent positive occultation events observed in our institute.
16th April 2020
Łukasz Tychoniec (Leiden University)
I will present an overview of observational efforts to study protostellar systems with ALMA in order to understand the conditions in which planets start to form. I will also describe the scientific plan of the JWST/MIRI European Consortium to observe star-forming regions.
9th April 2020
Dagmara Oszkiewicz (IOA)
SONATA13 is an NCN funded project aimed at verifying the Bottke et al. (2006) planetesimal formation and evolution scenario. According to that research planetesimals formed close to the Sun, in the terrestrial planet region and then scattered into the main asteroid belt. The remains of those planetesimals (so called V-type asteroids) can be observed in the current main belt. Derivation of spin statistics of those asteroids will help verify the Bottke et al. (2006) theory. In this presentation I will discuss the progress of the project and the preliminary results.
2nd April 2020
Edwin Wnuk (IOA)
26th March 2020
Dorota Krużyńska, Mikołaj Krużyński (AOI AMU)
“End-to-End-Procedure for satellite Orbit Catalogue from optical observation (E2EPOC)” is an ESA project in which AO AMU participate. The overall goal of the project is to design and verify observation procedures for the Polish SST activities. These procedures are planned to be end-to-end ones, i.e. complete procedures beginning from selection of objects to be observed and ending in update of orbits data of these objects in the orbital catalogue. In this presentation, we will present the goals of the project and the obtained results. We’ll focus on the procedures and tools used in orbit calculation and catalogue building.
19th March 2020
Edyta Podlewska-Gaca (IOA)
Thanks to adaptive optics imaging we are able to obtain high resolution images of asteroids and get new insight into their nature. I will present the results of such studies on VLT/SPHERE telescope. In particular it will be described how Hygiea became a candidate for a dwarf planet, and why Pallas looks like a golf ball.
12nd March 2020
Discussion of current affairs
5th March 2020
Open meeting with students
27th February 2020
Jean Surdej (University of Liège)
Magnificent phenomena do not only take place in the Universe (gravitational lensing) but also under the tree foliages which surround us. A short introduction to apprehend these nice phenomena will be given. We shall also report on a recent systematic search for multiply imaged quasars based upon observations carried out with Gaia.
30th January 2020
Radosław Poleski (OA UW)
Full understanding of planet formation and evolution cannot be achieved without finding exoplanetary analogs of planets observed in Solar System. In particular, analogs of Uranus and Neptune are hard to find due to their long periods and low luminosities. The origin of Uranus and Neptune cannot be explained using standard models of planet formation and ice giant exoplanets can shed light on formation of the widest-orbit planets. I will present currently known ice giant exoplanets and their connection to widely-discussed free-floating planets. I will also discuss possible future studies with NASA and ESA flagship missions: WFIRST and Euclid.
23rd January 2020
Agnieszka Kryszczyńska (IOA)
(60558) Echeclus was discovered in 2000 by Marsden and classied as a Centaur object. Surprisingly it presented several ourbursts: the largest ever observed for Centaurs in December 2005, and the smaller ones in May 2011 and in August 2016. On the pre-discovery archive images a cometary activity was also visible — that is why this object got also a cometary designation: 174P/Echeclus.
Lightcurves obtained between the outbursts did not show any cometary activity even during perihelion passage in April 2015, so they may serve as an input data for spin vector and shape modelling. For this purpose photometric data should cover different observing geometries. Collecting them for Echeclus is a long-lasting process because its long orbital period.
Combining all available lightcurves covering a 20 year observing period with three new lightcurves obtained in December 2019 at our RBT robotic telescope in Arizona, allowed us to determine the spin axis and shape model for this object. For that we used the SAGE technique developed by P. Bartczak from our Institute. Our model seems to be the first one obtained for a centaur based on only photomteric data.
9th January 2020
Piotr A. Dybczyński (IOA)
Our computer codes and stellar data sets allowed us to search for a potential source of the interstellar comet 2I/Borisov among nearby stars. The double star Kruger 60 seemed to be the best candidate but radial velocity data were lacking. This possibility was ruled out by the new radial velocity of the Kruger 60 center of mas obtained form private communications. We will describe methods of such an investigation and the limitations in making results publicly available.
More details:
https://arxiv.org/abs/1909.10952.
19th December 2019
Paweł Koleńczuk (IOA)
Near Earth Asteroid photometry is struggling with the problem of their observed high velocity in the sky during approaching Earth what causes image stretching of asteroid and/or stars on CCD frame (they leave trails). In such case typical differential photometry with circular apertures does not give good results. The solution is a pill aperture that perfectly reflects the shape of the trails. As a result, we save optimum signal-to-noise ratio. The shape of this aperture can be described as two half-circles connected by a rectangle. The use of the pill aperture is not limited to asteroid photometry. The problem of the observed high velocity in the sky also applies to artificial Earth satellites. Pill aperture can also eliminate the problem of star photometry during unexpected movement of the telescope e.g. during a
sudden gust of wind.
12nd December 2019
Karolina Dziadura (IOA)
The “Eclipse de Sol Chile 2019” project was an expedition to Chile to observe the total solar eclipse. The expedition was attended by students and Ph.D. students from Adam Mickiewicz University in Poznań, University of the Arts Poznań and the Nicolaus Copernicus University in Toruń. The total solar eclipse could be observed in Chile on July 2, 2019. For observations, we chose the mountain on the Pacific coast in the region of La Higuera (29.4544° S, 71.2472° W, 795 m a.s.l.). At this location, the total solar eclipse lasted 2 minutes 35.8 seconds. The first contact of the Sun with the Moon occurred at 19:22: 53.6 UT. The beginning, maximum and end of the total eclipse phase were 20: 38: 24.0 UT, 20: 39: 42.1 UT and 20: 40: 59.8 UT respectively. The sun was then at an altitude of 13.6° and azimuth 306.8°. For registration we used: Canon 6D camera with a 100-400 mm telephoto lens (photographs), Canon 650D camera with a 150 mm lens (film), Nikon D90 camera with a 200 mm lens (photographs), Canon 700D camera with 800 mm lens (photographs). We recorded the Sun trajectory using a meteorological device called a heliograph.
5th December 2019
Monika Kamińska (IOA)
Optical observations of objects in low Earth orbits
28th November 2019
David Vokrouhlický (Astronomical Institute of Charles University, Prague)
Traditionally, long-period comets (LPC) are defined by their huge orbital periods: 200 yr at minimum, but many have effective orbital periods as long as millions of years. At the first sight, they are mysterious visitors to the inner Solar system on incomparably elongated orbits from its extreme outskirts. Yet, their population may be well understood using advances in our knowledge of the Solar system early evolution and a flood of new and accurate orbital data. I shall describe an evolutionary model for the LPCs that reasonably well matches their orbital architecture. Admittedly, it is less successful in describing their observed flux to the inner Solar system, though I shall discuss plausible reasons for this mismatch. The model allows to make predictions which could be tested by LSST observations within the next decade.
21st November 2019
Arkadiusz Hypki (IOA)
Project gaia@home (former GAVIP-GridComputing) is an ESA project run by Poznan Astronomical Observatory staff which will add additional features to the Gaia archive by incorporating CPU power of volunteers’ computers of the BOINC grid (best known of its SETI@Home project).
gaia@home eventually will allow to define a series of jobs which will be able to read entire Gaia archive and compute some CPU intensive jobs on the BOINC platform (best known from SET@home project). The users, in order to use the GAVIP-GC software will provide source code to deal with their scientific problem. Everything else (e.g. reading data from Gaia, communicating with BOINC, downloading the results) will be done by gaia@home software.
During the seminar I will present the current status of the project.
14th November 2019
Anna Bartkiewicz (UMK Toruń)
High angular resolution studies of the 6.7 GHz methanol maser emission provide one of the best existing tools for deriving 3D kinematics around high-mass proto- or young stars. Regions that are hidden in the dense environments and are not easily reachable at other wavelength ranges. Particularly, multi-epoch, sensitive observations using the very long baseline interferometry networks are successfully used to investigate proper motions of single maser clouds in high-mass star forming regions.
I will present recent studies of sources that showed ring-like structures at the 6.7 GHz line and were discovered in the Torun survey with the 32-m radio telescope. Using the European VLBI Network over 10 years and obtaining images of emission with miliarcsecond angular resolution, we can follow detailed kinematics (tangential velocities of order a few km/s) of masing clouds in the vicinity (ca. 1000 au) from central stars. Unexpectedly, masers are expanding from the centres of the ring, indicating a physical relation to an outflow or an expanding bubble rather than a disc.
7th November 2019
Krzysztof Kamiński (IOA)
In September/October 2019, four domes and telescopes were installed in Chalin. We present the assembly of a new satellite observation system PST3. The basic stages of system construction will be discussed. Photo coverage from the construction process will be presented. Basic parameters, technical details of five telescopes and other equipment will be discussed. System capabilities, further construction plans and test images from some telescopes will be presented.
24th October 2019
Magdalena Otulakowska-Hypka (IOA)
Optical interferometry is a method of astronomical observations that gathers light collected by several telescopes observing the same object simultaneously. It allows to measure sizes and even exact shapes of astronomical objects. We use optical interferometry to examine a large number of symbioticstars. Our observations and analysis will allow not only to determine the size of the stars, but thanks to reaching their innermost regions, we will be able to observe directly the extension of the red giant’s surface due to tidal forces. I will present the first results of this project.
17th October 2019
John Williamson (University of Glasgow)
A new theory of light and matter incorporates a complex scalar field, responsible for the mutual confinement of light and rest mass in “elementary” particles. This field parallels many of the observed properties of dark matter and dark energy. These include the gravitational effects, the property of the observed increase in the rate of “expansion” of the universe, the transparency of the substance to light and the non-observation of dark matter to date. This invisibility does not mean that the substance is immune to experiment. Experimentally observable effects of this field in the nearby solar system, the local galactic cluster and the wider universe will be discussed. As well as the usual properties associated with dark matter/energy such as gravitational lensing, the observed expansion of the universe and galactic rotation, the talk will discuss, among other things, solar coronal heating, high energy particle generation (x and gamma rays and high-energy charged particles), and matter-antimatter asymmetry in the physical universe.
John Williamson worked at CERN for 7 years, in nano engineering in Philips for 5 years, and as an associate professor in the College of Science and Engineering in Glasgow University for 27 years. He is currently the director of Quicycle an international group devoted to the advancement of science. He has published widely in the fields of experimental physics, nano-engineering, and in theoretical physics. He has (co-) authored over a hundred papers. He has over twelve thousand citations in peer-reviewed papers and an h-index of 45.
10th October 2019
Rita Wysoczańska (IOA)
Since 1950 when Oort published his paper on the origin of comets a continuous search for the stars which were able to perturb cometary motion has been conducted. The aim of this presentation is to discuss two cases in which the data obtained from observations were used and stellar perturbations (of different intensity) on cometary motion were detected. Our results show how different the dynamical evolution of comets would have looked when their motion was considered only in the Galactic gravitational potential. Uncertainties both in stellar and cometary data were carefully taken into account. Our analysis indicates that the occurrence of stellar perturbations on cometary motions is very rare and the uncertainties of these effects are hard to estimate.
Talks in 2018/2019:
6th June 2019
mgr Emil Wilawer (IOA)
At the beginning of XXI century astronomy entered the Big Data era, in which robotic telescopes produce petabytes of data. Most of them consist of CCD images which require automatic measurements by the specialized photometric pipelines. In our Institute we still use a traditional method of aperture photometry which requires frequent manual intervention. While beeing well tested, this approach starts showing its weekness when faced with the increasing inflow of observing data. It also lacks photometric callibration which recently became a routine procedure in differential photometry thanks to the sky surveys (SDSS, PanSTARSS) which released their high accuracy photometric measurements of millions of stars. In the talk I will present the use of the photometric pipeline of Michael Mommert for the automatic photometry of asteroids and briefly describe main stages of the computations The application of this procedure for derivation of asteroid phase curves will also be shown.
30th May 2019
mgr Piotr Guzik (OA UJ)
Discovered last year, the first recognized interstellar visitor in Solar System, 1I/2017 U1 (Oumuamua) is the long-sought link between our own Solar System and systems around other stars, heralding an onset of a new field in astronomy. Our group has played an important role in the effort of characterizing this unique body. We were awarded 12 hr of DDT on the Gemini North 8.1-m telescope. As a result, we obtained the highest quality photometric and spectroscopic data, which have revealed some remarkable and unexpected properties. I will review the current state of knowledge on Oumuamua, discuss the impact of this body on science and society, and speculate on possible future avenues.
In the second part of my talk, I will present our first dedicated search for dust trails of asteroids, that forms along the asteroids orbit as a result of their disruptions. The trail can be observed for many years, as showed by the studies of two recently disrupted asteroids, P/2010 A2 and P/2012 F5. We argue that a dedicated survey with a large telescope can possibly detect much fainter (thus older) trails – precious remnants from historical disruptions – thereby providing basis for detailed research into the causes of the disruption. A pilot survey was conducted by our team at SALT. We have successfully detected the known ultra-faint trail of the disrupted asteroid P/2012 F5 – proving the concept in terms of technical feasibility. I will present the main science goals of the survey, discuss the results from the pilot phase, and draw conclusions for the full phase which has been recently initiated.
23rd May 2019
mgr Jacek Haponiak (IOA)
“Colmbo top” model describes rotational dynamics of a rigid body moving around the material point under the efect of gravitational interaction. It can be applied to the analysis of Earth’s Moon rotation, Solar System planets, exoplanets, moons, asteroids and space debris. During presentation “Colombo top” model, its aplications and analitical solution will be shown.
16th May 2019
prof. Tomasz Kwiatkowski (IOA)
Working under a contract to ESA we are preparing a web-based Service for Archival NEO Orbital and Rotational Data Analysis (SANORDA). It includes a NEO Period Determination Tool (NPDT) which takes asteroid lightcurves from a database and uses them to derive their rotation periods. The algorithm is based on a well known Fourier series analysis and implemented as a python program called PerFit. In the talk I will present a typical use cases of the NPDT service, which is currently in a beta stage. Using PerFit I will also show how the uncertainties in the asteroid lightcurves influence the accuracy with which their synodic periods can be derived.
25th April 2019
mgr Volodymyr Troiansky (IOA)
Basaltic V-type asteroids and their fragments are collisional remnants of planetesimals that existed 4 billion years ago. Their distribution, physical and dynamical properties provide important constrains on processes such as planetary differentiation, planet formation and evolution of planetary systems.
Asteroids with the prograde sense of rotation, located in the inner Main Belt, that have semi-major axes of their orbits smaller than that of Vesta, are less likely to have migrated from Vesta due to thermal forces dragging them outwards (the Yarkovsky effect).
Assuming that the inner Main Belt is populated only by the Vesta like objects, around 81% of asteroids in the so-called scattered resonances region are expected to have retrograde sense of rotation. Similarly 40% of objects in the low inclination region, should have retrograde rotation. Substantial surplus of asteroids that have prograde rotation could indicate that also other planetesimals (different from Vesta) contributed to this population. Those predictions are verifiable via photometric studies in which asteroid lightcurves are used to derive senses of rotation.
4th April 2019
prof. Piotr Dybczyński (IOA)
Almost 60 papers were published on the first macroscopic body coming from an interstellar space. Both ground-based and space-born most powerful telescopes observed it for many hours. Unfortunately such a short visit caused substantial lack of knowledge on its nature and as a result we have more questions than answers. It appeared even a suggestion that it is an alien spacecraft, rather ruled out by the majority of the astronomic community. Anyway, strange and mysterious name: ‘Oumuamua fits very well in this case.
28th March 2019
mgr Patrycja Bagińska (IOA)
I want to present a study of disk instabilities in black hole binaries in which X-ray novae outbursts were observed. Soft X-ray transients (SXTs) are the subclass of accreting low-mass X-ray binaries (LMXB) and they spend most of their lifetime in quiescent state. Those objects an be discovered only during outburst phase when they become one of the brightest sources in the X-ray sky. Almost all of SXTs are recurrent sources. It was noticed that intervals between outbursts may vary from tens of days to decades or maybe even longer, as only a few systems have shown two or more outbursts. Usually we observe outbursts of the regular, symmetric shape or so called fast rise exponential decay (FRED) shape which is typical for X-ray novae outburst. I will present numerical simulations of instability process that occurs in X-ray novae sources. I’ve calculated models which predict time dependent evolution of ionization instability in an accretion disk around black hole, assuming viscosity parameter to be proportional to the total pressure. As a result of modelling I get confirmation that the ionization instability in the examined sources is responsible for occurrence of characteristic X-ray novae outbursts. This study shows how analysis depends on assumed global accretion disk parameters and chemical abundances.
21st March 2019
mgr Mikołaj Krużyński (IOA)
Satellite catalog contains orbits of about 20000 objects. Maintenance of up-to-date catalog requires systematic observations of all objects. To obtain necesarry data a high precision measurements of satellite positioning and precise timing are required. An appropriate process of observation and reduction is required, as well as specialized software.
Although observations of satellite objects have been carried out for over 60 years, the use of telescopes in the case of cataloging objects moving below 2000 km above the Earth’s surface is a novelty. The technological development that has taken place over the last decade allowed for high quality astrometric observations of satellites in LEO orbits (Low Earth Orbit).
Observations of LEO objects were performed using the RBT telescope over the past few years. We are able to analyse these observations and determine orbits. Currently we want to have possibility to use other type observations. In this talk I will present preliminary results of combining laser ranging and astrometric observations used in the orbit determination problem.
14th March 2019
dr hab. Michał Michałowski (IOA)
I will present the results of observations (including those with RBT/PST2) of a gamma-ray burst (GRB) 171205A and the associated supernova (SN) 2017iuk, which led to the discovery of a hot gas cocoon. This was possible because observations started very early and the jet emission was weak. This gives support to the theoretical models of GRB/SN explosions, which predicted the existence of such a cocoon. This discovery opens the possibility to study internal processes during explosions of very massive stars, and hence will shed light on the understanding of the production of heavy elements. In case you miss this seminar, I will also give it at the Faculty of Physics on 3rd of April:
http://zon8.physd.amu.edu.pl/~miran/seminars.html
24th January 2019
prof. Mirosław Giersz (CAMK PAN)
I will very briefly describe the basic ideas behind the Monte Carlo MOCCA code and discuss the set-up of the MOCCA Survey Database project – a database containing thousands of Monte Carlo (MOCCA) simulations of real globular clusters. Afterwards, I will list and shortly describe projects connected with the analysis of the Database from the point of view of compact objects. Projects which deal, among others, with: BH and NS populations in star clusters and their interactions, BH Subsystems and IMBHs and their observational signatures, and many more. Finally, I will discuss recent developments of the MOCCA code and planed simulations for the MOCCA Survey Database II.
17th January 2019
mgr Krystian Iłkiewicz (CAMK PAN)
Cataclysmic variables (CVs) are interacting binary stars that consists of a degenerate white dwarf accreting mass from a normal star donor. Our understanding of evolution of such systems have been challenged by properties of their known population, such as white dwarf mass distribution, orbital period distribution and their space density. With the recent developments of population synthesis codes we are able to reproduce the CV population characteristics. However, there are still unsolved problems posed by the population of classical novae among the CVs, such as for example why there is only one system known to have both dwarf nova and classical nova outbursts. In my talk I will discuss the recent developments of population synthesis codes as well as my work on understanding of classical novae population using population synthesis.
10th January 2019 (two shorter talks)
mgr Aleksandra Leśniewska (IOA)
Binary stars are very important topic of astrophysical research. Using the data from photometric and spectroscopic observations, we are able to determine much more physical parameters of the system’s components than in the study of a single star. We obtain information not only about effective temperatures, metallicity, rotation velocity, but what is the most important, masses and radii of two components. Compact binaries become crucial when considering the evolution of stars and their influence on the later generations of astronomical objects. The system composed of a white dwarf and a red giant, is called symbiotic star. Researches on these types of objects contribute to a more accurate understanding of the geometry of binary stars and mechanisms in these systems. Our work is dedicated to modeling the physical parameters of the SY Muscae, symbiotic star in the southern sky. Based on photometric and spectroscopic observational data, in the infrared and visible range, using the PHOEBE program we created a model of light curves and radial velocity. This model clearly describes the shape and dimensions of the components of SY Muscae. The result of the analysis is a model of light curves, radial velocity, and a set of SY Muscae physical parameters. Based on the comparison of the results obtained by us with the results in the literature, it turns out that SY Muscae is a typical symbiotic star.
Dust production is a very important issue in galaxy evolution. Unfortunately, we are still unable to determine its formation mechanism. I will present the investigation of dust production in nine galaxies at the redshift at z > 6, for which dust emission has been detected. In recent years, more accurate measurements were made using the most powerful instruments, eg ALMA, which contributed to better estimates of luminosities and sizes, and thus to determine the masses of gas, dust and stars in the studied galaxies. We conclude that asymptotic giant branch (AGB) stars did not contribute to the dust formation significantly in these Early Universe galaxies, and that supernovae are unlikely to produce the bulk of the dust mass. I will discuss how the advent of future large telescopes will contribute to this topic.
21st December 2018 (Optional seminar at 13:30)
dr Anna Kapińska (National Radio Astronomy Observatory, USA)
The new continuum radio surveys delivered in recent years are an outstanding resource in addressing long-standing questions in modern astrophysics. In this talk I will focus on the lowest radio frequencies (<230MHz) currently accessible with the ground based new-generation radio facilities. Specifically, I will present our recent results on radio spectral energy distributions and star formation of Sculptor Group galaxies and Magellanic Clouds, which we observed with the Murchison Widefield Array (MWA) — a low frequency SKA precursor from an Australian outback. Although of low angular resolution, especially as compared to ALMA, these sensitive low frequency observations are very complementary to GHz observations, and necessary for a complete picture of physical processes occurring in galaxies.
20th December 2018
dr Agata Makieła (University of Kent, UK)
In the summer 2017 I was involved in the NASA Frontier Development Lab, an intense 8-week study concentrated on tackling topics important to NASA using machine learning tools. During the programme interdisciplinary teams of early career researchers were looking at issues related to planetary defence, space weather, and space resources. The team I was a part of investigated shape modelling of near-Earth asteroidsfrom radar data. These asteroids are the Earth’s closest neighbours in space, most accessible by space flight and with a potential for causing a threat to the planet. Even though they are constantly monitored, detailed characteristics, like shapes and sizes, are available for only a selected few. Physical models are required to successfully plan spacecraft missions and set up impact mitigation strategies. Additional incentive is in learning know how our space environment works and evolves. Reconstructing asteroid shapes and spins from radar data is, like many inverse problems, a computationally intensive task. Shape modelling also requires extensive human oversight to ensure that computational methods find physically feasible results. In this talk I will discuss the results of our work at NASA Frontier Development Lab 2017, exploring the application of machine learning tools to the shape modelling task.
13rd December 2018
dr Krzysztof Hełminiak (CAMK PAN)
In years 2015-2017 we have conducted a programme of high-resolution spectroscopic observations of a sample of detached eclipsing binaries (DEBs) observed by the Kepler satellite in its original mission field. With the 1.88-m telescope of the Okayama Astrophysical Observatory and its HIDES spectrograph, we have collected 290 spectra of 23 systems, in order to analyse them thoroughly and as comprehensively as possible. The sample contains variety of different objects (giants, low-mass stars, multiples, pulsators, planet hosts), many of which were studied for the first time, and with parameters derived very precisely. In my semi-formal talk I will present a subjective selection of 10 systems from our sample that I find the most interesting, intriguing and important for the stellar astrophysics. Kittens will be included.
10th December 2018 (Optional seminar at 16:00)
dr José Ricardo Rizzo Caminos (Centro de Astrobiologia, Madrid)
Opportunities using radio astronomy facilities in Madrid
6th December 2018
dr Arkadiusz Hypki (IOA)
GAVIP-GridComputing (shortly GAVIP-GC) is an ESA project run by Poznan Astronomical Observatory staff which will add additional features to the Gaia archive by incorporating CPU power of volunteers’ computers of the BOINC grid (best known of its SETI@Home project). GAVIP-GC eventually will allow to define a series of jobs which will be able to read entire Gaia archive and compute some CPU intensive jobs on the BOINC platform. The users, in order to use the GAVIP-GC software will have to provide only source code to deal with their scientific problem. Everything else (e.g. reading data from Gaia, communicating with BOINC) will be done by GAVIP-GC software. During the seminar I will present the current status of the project and our plans for the next milestones.
29th November 2018
prof. David Vokrouhlický (Astronomical Institute of Charles University, Prague)
Asteroid families are clusters of small bodies that move about the Sun on fairly similar orbits. They are outcome of a collisional disruption of a common parent asteroid. Therefore, analysis of members in families can bring us interesting information about the fragmentation process at high-energies and, otherwise inaccessible, interior properties of asteroids. The most valuable in this type of studies are young families, in which the evolutionary processes had not enough time to confuse the results. I will review the past two decades of a race to find ever younger families in the main belt, demonstrating also what kind of unexpected results it brought along.
22nd November 2018
prof. Edwin Wnuk (IOA)
15th November 2018
prof. Jerzy Krzesiński (OA UJ)
We are showing that some of the exoplanetary signatures found in the light curves of a couple of sdBV star systems (KIC 5807616 and KIC 10001893) might be of different source than exoplanet light reflection or radiation effects. We point out that at least one signature can be explained by a combination of pulsating frequencies of the host star and others might be just artifacts. Using simulated light curves we also analyzed frequency changes of the signal around 0.256 c/d (~3.9 day) visible in the Fourier transform of the KIC 10449976 sdO star light curve. Our simulations show that it is difficult to reproduce the observed signal frequency variations by the weather changes in the exoplanet atmosphere.
8th November 2018
dr Justyna Gołębiewska (IOA)
From the launch of the first artificial satellite: Sputnik in 1957, more than 5000 launches have placed 8000 satellites into orbit, of which about 4800 remain in space. In addition to operational satellites in orbit there are over 12000 space debris. To to ensure safety in space European Space Agency (ESA) as well as European Commission carries out the Space Situational Awareness (SSA) Programme, consisting of three segments. One of these segments is the Space Surveillance and Tracking (SST) system that comprises detecting,cataloguing and predicting the orbits of objects orbiting the Earth, and related applications. We are showing our results in two of main segment of SST: Re-entry Predictions for Risk Objects and Collision Warning.
25th October 2018
prof. Tadeusz Jopek (IOA)
We have made an extensive search for grouping amongst the near Earth asteroids (NEAs). We used two D- functions and rigorous cluster analysis approach. We have found several new groups (associations) among the NEAs: the objects moving on similar orbits with small minimum orbital intersection distances (MOID) with the Earth trajectory.
18th October 2018
dr Krzysztof Kamiński (IOA)
In recent years European Space Agency (ESA) as well as newly established European Space Surveillance and Tracking Consortium (EU SST) — both of witch Poland is a member state — have increased the effort towards a new satellite tracking system for Europe, that would be independent from external sources of satellite orbital data. Such a system is typically composed of several radar sensors for tracking Low Earth Orbit (LEO) satellites and several optical sensors for higher orbit targets. However recent developments in optical telescopes enabled an efficient tracking of LEO satellites with an equipment 2 to 3 orders of magnitude cheaper than a typical satellite radar. Of course optical satellite sensing suffers from a daytime and bad weather limitations to a much greater extent than a satellite radar. Therefore it is reasonable to simulate an optical satellite tracking network, using a global cloud-fraction statistics, in order to estimate possible outcome from such an entertainment. In this seminar I present preliminary results of simulations showing weather it is possible to build an efficient global optical satellite tracking network, what locations should be selected on Earth, and how many sites should be used in order to have a very high probability of observing each target every day.
11st October 2018
dr hab. Agnieszka Pollo (OA UJ)
I will present recent results from the VIMOS Public Extragalactic Redshift Survey (VIPERS). VIPERS – with its \sim 90,000 spectroscopically measured galaxies, a large volume (5 x 10^7 h^(-3) Mpc^3), and an effective spectroscopic sampling > 40% – can be considered the state-of-the-art counterpart of “local” (z<0.2) cosmological surveys but targetting the epoch at z \sim 1. I will summarize our newest results on the properties of galaxies and large scale structure and their common evolution since z \sim 1. How galaxies changed during the last 8 bln years? What are the properties of the 3D cosmic structure emerging from VIPERS measurements and what they can they tell us about cosmological parameters? And, most interestingly – what remains unknown and why do we need even larger surveys in the future?
4th October 2018
Administrative matters
Talks in 2017/2018:
21st June 2018
mgr Grzegorz Dudziński (IOA)
The volume of an asteroid shape model, when combined with the size and mass estimates, is essential in bulk density determination – one of the most important physical parameters that allow us to peek inside asteroids and make conclusions about their inner structure. The shape model uncertainty propagates to volume, and analogously to any
other property determined from the model, affecting every conclusion drawn for a population of small bodies under scrutiny. There definitely exists a compelling need for a procedure of quality and uncertainty assessment of asteroid models. I would like to present modelling-technique-independent uncertainty assessment method based on gen-
erating clones of investigated model. By far, the most abun-dant data type for the most numerous target sample is disc-integrated relative photometry in visual bands and the majority of published asteroid models are based solely on it. For that reason the presented method deals with photometric lightcurves and absolute sparse data.
14th June 2018
dr Milena Ratajczak (IA UWr)
Several aspects of stellar evolution can be tested with B-type stars in eclipsing binary systems. Finding tighter constraints on the value of the convective core overshooting parameter is one of the most valuable among them. Precise photometry and high-resolution spectroscopy with high SNR are required to achieve that goal, but since many of the targets are bright enough, the challenge is fair. The approach to examine the aforementioned aspect of stellar evolution using observations of B-type stars obtained with a wide range of spectrographs, as well as BRITE-Constellation satellites, will be presented.
7th June 2018
dr Magdalena Otulakowska-Hypka (IOA)
The disk instability model attributes the outbursts of dwarf novae to a thermal-viscous instability of their accretion disk, an instability to which nova-like stars are not subject. We aim to test the fundamental prediction of the disk instability model: the separation of cataclysmic variables (CVs) into nova-likes and dwarf novae depending on orbital period and mass transfer rate from the companion. We analyse the lightcurves from a sample of ~130 CVs with a parallax distance in the Gaia DR2 catalogue to derive their average mass transfer rate. The method for converting optical magnitude to mass accretion rate is validated against theoretical lightcurves of dwarf novae. Dwarf novae (resp. nova-likes) are consistently placed in the unstable (resp. stable) region of the orbital period – mass transfer rate plane predicted by the disk instability model. None of the analyzed systems present a challenge to the model. These results are robust against the possible sources of error and bias that we investigated. The disk instability model remains the solid base on which to construct the understanding of accretion processes in cataclysmic variables.
24th May 2018
mgr Przemysław Mróz (OA UW)
Theories of planet formation predict the existence of a population of unbound (free-floating) planets. Gravitational microlensing provides a unique tool for studying these objects. The first results of Sumi et al. (2011) claimed that Jupiter-mass free-floating planets are as common as main-sequence stars. However, these results appear to disagree with censuses of substellar objects in young clusters and star-forming regions and with predictions of planet formation theories. I will present new results of the analysis of a ten times larger sample of microlensing events discovered by the OGLE-IV survey during the years 2010-2015. They shed new light on the population of free-floating planets.
17th May 2018
mgr Ewa Kosturkiewicz (AOI AMU)
Spectroscopic observational campaign of the delta Ceti star in 2014 – 2017 – preliminary results
10th May 2018
mgr Krzysztof Langner (AOI AMU)
Kustaanheimo-Stiefela (KS) transform is used to regularize and linearize Kepler problem and t transform it into harmonic oscillator. Regularization changes the independent variable (time) and can improve accuracy of numerical propagation of orbits, especially when eccentricity is high. Lissajous variables are used as action-angle variables for harmonic oscillator. In my presentation I will show these two transforms using canonical formalism and extension for orbits with explicit time dependent perturbation.
26th April 2018
dr Agnieszka Słowikowska (CA UMK)
In my talk, I will describe the basic concept of polarimetry as well as the most common use of it as a tool in astronomy. I will present a few polarimeters that are in use at the moment. Additionally, I will discuss our recent polarimetry study of white dwarfs and neutron stars.
19th April 2018
prof. Andrzej Niedzielski (CA UMK)
Stars beyond the MS are frequently avoided in planet searches because they are known to exhibit various types of variability: RV variations of unknown origin were pointed out to be common in red giants (RGs) by Walker et al. (1989), and multiple pulsation modes are often present. In addition, the rotation of starspots across the stellar disk can affect the spectral line profiles of these stars (Vogt et al. 1987; Walker et al. 1992; Saar & Donahue 1997). However, soon after the first discovery (ι Dra b Frink et al. 2002), searches for planets around stars beyond the MS have become recognised as important in building a complete picture of planet formation and evolution for several reasons. First, they allow extending the reach of the most versatile RV technique, which is not applicable on the MS because of the high effective temperature of the stars and their fast rotation rates, to objects with masses significantly higher than solar (e.g., o UMa, a 3 M⊙ giant with a planet – Sato et al. 2012). Second, the planetary systems around evolved stars are much older than those around MS stars, and therefore they are suitable for long-term dynamical stability considerations. Planetary systems around giants are also subject to changes induced by stellar evolution, and therefore are suitable for studies of star – planet interactions, and last but not least, evolved planetary systems carry information on the initial population of planetary systems to be found around white dwarfs. It is no surprise then that several projects devoted to searches for RV planets that orbit RGs were launched. One of the largest of them is the PennState – Toruń Centre for Astronomy Planet Search (PTPS, Niedzielski et al. 2007; Niedzielski & Wolszczan 2008a,b).
In my talk I will present the sample of PTPS, current status of our planet search and the most recent discoveries. I will also discuss some properties of the exoplanets around evolved stars from the PTPS perspective.
12nd April 2018
prof. Agata Różańska (CAMK)
X-ray astronomy requires satellites to make progress in searching the distribution of hot matter in the Universe. Approximately 15 years period of time is needed for full construction of the flight instrument from the mission concept up to the launch. A new generation X-ray telescope ATHENA (the Advanced Telescope for High Energy Astrophysics) was approved by European Space Agency as a large mission with a launch foreseen in 2028. I will talk about how ATHENA will help us to study Hot and Energetic Universe, and I will present Polish involvement to the mission development.
5th April 2018
dr Michał Drahus (OA UJ)
Disruptions of asteroids are often viewed as ancient events leading to the
formation of asteroid families and pairs, binary and multiple systems, and
discrete dust bands within the Zodiacal cloud. But thanks to the
remarkable progress in solar system science over the last decade, we can
now directly observe asteroidal disruptions occurring before our eyes.
Various lines of evidence suggest that the disruption can be a consequence
of a rapid rotation resulting from a long-term spin-up, or a result of a
hypervelocity collision with another minor object. Up until recently the
two mechanisms were difficult to distinguish because of the unknown
rotation rates of the disrupting small asteroids, but this has changed
after our team investigated the recently disrupted asteroid P/2012 F5.
Using the Keck II telescope atop Mauna Kea we discovered several fragments
of the object and obtained the highly anticipated measurement of the
rotation rate, which turns out to be the fastest known among active
asteroids and is fast enough to support the rotational disruption
scenario. Further observations with the Hubble Space Telescope have
revealed that the system is in fact the first ultra-young asteroid family
identified to date, and given its likely formation via rotational
disruption, it can also be the first known asteroid family of
non-collisional origin.
22nd March 2018
prof. Agnieszka Kryszczyńska (AOI AMU)
The NEO-DECS web service an open access central service of structured
metadata on NEOs, as well as a platform for collaboration among NEO
researchers, using elements well known in social networking like user
profiles, forum facility, private messaging, etc. Such service shall make
it easy to locate necessary databases and services on NEOs, learn about
forthcoming conferences and workshops, and allow for advertising new
observing programs, telescopes availability, numerical tools, etc.
During the talk I will demonstrate NEO-DECS based on several use cases.
15th March 2018
Seminar canceled
8th March 2018
prof. Edwin Wnuk (AOI AMU)
In December 2017 Polish Space Agency announced the National Space Programme
(KPK) for Poland. After concultations with all interested parties KPK
shall be accepted in the first quarter of 2018. Next the first calls
shall be announced covering a broad range of space studies, including
astronomical reserach.
Quadruple stellar system in the 1:1 resonance
During the talk three highest priority KPK projects shall be presented as
well as the areas in which the first calls for grant proposals shall be
announced. Guidelines for grant applications as well as the planned KPK
budget shall be discussed.
1st March 2018
dr Magdalena Polińska (IOA)
We would like to present results for the two objects, GT UMa B which is a part of multiple system and for the eclipsing binary star BD-00 2862. The spectra for the first object were obtained with the spectrograph ESPERO mounted on the 2-m telescope in Rozhen and for the second one with PST1 (Poznań Spectroscopic Telescope 1) located in Borowiec. For those stars we estimated atmospheric parameters, such as: the effective temperature, surface gravity, metallicity and the projected rotational velocity. The observed spectra were compared with the set of synthetic spectra calculated with the iSpec code.
22nd February 2018
dr Arkadiusz Hypki (IOA)
The amount of data in science which is delivered nowadays increases like never before. It applies for all fields of research. However, physics and astrophysics appear to push the requirements for data storage and analysis to the boundaries. With already existing missions like Gaia and for future projects like LSST the need for reliable and scalable data storage and management is even higher. The amount of data for many projects is too big for simply processing with bash or python scripts. Tools which would allow easy data analysis are crucial in research these days.
BEANS software is a web based, easy to install and maintain, new tool for interactively distributed data analysis. It provides a clear interface for querying, filtering, aggregating, and plotting data from an arbitrary number of datasets and tables.
During the seminar I will present features of the BEANS software and show how it can help scientists to analyze huge datasets.
25th January 2018
Dr An-Li Tsai (AOI AMU)
Galactic molecular outflows affect star formation activities in galaxies. This process is important for galaxies evolution. I will talk about case studies on two nearby starburst galaxies NGC 2146 and NGC 3628.
18th January 2018
Prof. Joanna Mikołajewska (CAMK)
I will present and discuss recovery of the binary underlying the classical nova of 11 March 1437 recorded by Korean royal astronomers whose age is independently confirmed by proper motion-dating. I will also discuss the physical characteristics and the present evolutionary status of the binary system responsible for the nova outburst based on preliminary results of our ongoing extensive observations.
11st January 2018
Prof. Michał Ostrowski (OA UJ)
New gamma-ray observatories: Cherenkov Telescope Array (CTA)
4th January 2018
Dr Dagmara Oszkiewicz (AOI AMU)
SANORDA (Service for Archival NEO Orbital and Rotational Data Analysis) is an ESA funded project aimed at archiving light curve and orbital data. In work package WP1200 we focus on determining historical orbits of all NEOs to reproduce their orbital improvement history starting from discovery onwards. The historical orbits may aid better observation planing and improve our understanding of astrometric biases present in the Minor Planet Centre database. We focus on two orbit computation methods: the ranging method and the traditional linearised least squares method. For asteroids with short observational arcs (shortly after discovery) we use ranging method and when the phase space of possible orbital solutions is sufficiently contained (close to Gaussian distribution) we switch to least squares. Those orbital histories are being reproduced for around 17 000 NEAs, which will result in almost 2 000 000 orbits. The project is ongoing and the final database is expected in 2018.
14th December 2017
Prof. Sławomir Breiter (AOI AMU)
Quadruple stellar system in the 1:1 resonance
7th December 2017
Prof. Piotr Dybczyński (AOI AMU)
On the dynamical history of the recently discovered interstellar object A/2017 U1
30th November 2017
Dr Tomasz Kwiatkowski (AOI AMU)
A new catalogue of asteroid lightcurves
23rd November 2017
Dr Przemysław Bartczak (AOI AMU)
Asteroid models uncertainty
16th November 2017
Prof. David Vokrouhlický (Astronomical Institute of Charles University, Prague)
Origin and evolution of short-period comets
9th November 2017
Dr Krzysztof Kamiński (AOI AMU)
New satellite tracking camera in Poznań
26th October 2017
Dr Michał Michałowski (AOI AMU)
The first observation of radiation from colliding neutron stars – the sources of gravitational waves
19th October 2017
Dr Paweł Kankiewicz (Jan Kochanowski University, Kielce)
Dynamical studies of asteroids in retrograde orbits
12nd October 2017
Dr Anna Marciniak (AOI AMU)
The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation
Talks in 2016/2017:
8th June 2017
Mikołaj Krużyński (AOI AMU)
SST observations – not only with PST2
1st June 2017
Dr Toni Santana-Ros (AOI AMU)
A ménage à quatre of European projects linked by the study of asteroids
25th May 2017
Krzysztof Langner (AOI AMU)
New approach to Kustaanheimo-Stiefel transform
18th May 2017
Ewa Kosturkiewicz (AOI AMU)
Study of beta Cephei-type pulsating stars
11st May 2017
Dr Michał Michałowski (AOI AMU)
Dust, galaxies and gamma ray bursts
27th April 2017
Patrycja Bagińska (AOI AMU)
X-ray novae: analysis and modelling of outbursts
20th April 2017
Magda Butkiewicz-Bąk (AOI AMU)
Photometry of asteroids in crowded star fields
6th April 2017
Dr Anna Marciniak (AOI AMU)
Photometric survey, modeling and scaling of long-period and low-amplitude asteroids
30th March 2017
Prof. Tadeusz Jopek (AOI AMU)
The Morasko meteorite chain fall
23rd March 2017
Dr Magdalena Polińska (AOI AMU)
Spectroscopic study of delta Scuti stars
16th March 2017
Prof. Witold Szczuciński (Institute of Geology, Adam Mickiewicz University)
Geological and environmental effects of small hypervelocity meteoroid impacts – insights from Morasko impact
9th March 2017
Łukasz Gruszka (AOI AMU)
Legal Time Distribution System: a technique for transfering accurate time
2nd March 2017
Dr Krzysztof Kamiński (AOI AMU)
Software tools for planning and reduction of astrometric observations of Earth’s Artificial Satellites
23rd February 2017
Dr Przemysław Bartczak, Grzegorz Dudziński (AOI AMU)
GAVIP-GC
Dr Wojciech Dimitrow (AOI AMU)
A report from ESO workshop
26th January 2017
Grzegorz Dudziński (AOI AMU)
SAGE development status; invertion of asteroids’ radar echo observations
12nd January 2017
Dr Jerzy Nawrocki (OAG CBK PAN, Borowiec)
Caesium fountain in Borowiec
15th December 2016
Dr Tomasz Kwiatkowski (AOI AMU)
The olivine-dominated composition of the Eureka family of Mars Trojan asteroids
8th December 2016
Dr Krzysztof Kamiński (AOI AMU)
SST observations with PST1 and PST2
24th November 2016
Prof. David Vokrouhlický (Astronomical Institute of Charles University, Prague)
Tilting Saturn during planetary migration
17th November 2016
Dr Jan Janik (Masaryk University, Brno)
Hot stars in Brno
10th November 2016
Filip Berski (AOI AMU)
Close approach of Gliese 710
3rd November 2016
Dr Przemysław Bartczak (AOI AMU)
SAGE: modelling asteroid shapes based on light curves and radar data
27th October 2016
Dr Arkadiusz Hypki (Leiden Observatory)
MOCCA – current state and [Breiter] future ahead
20th October 2016
Dr Dagmara Oszkiewicz (AOI AMU)
Searching for parent bodies of anomalous HEDs
13rd October 2016
Dr Magdalena Otulakowska-Hypka (AOI AMU)
Close binary stars
6th October 2016
Michał Żołnowski, Grzegorz Duszanowicz, Marcin Gędek,
Michał Kusiak, Rafał Reszelewski (6ROADS)
SST and NEO observations with 6ROADS telescope network
