Light curve feature extraction from astronomical source

Astronomy is entering the era of large surveys of the variable sky such as Zwicky Transient Facility and forthcoming Legacy Survey of Space and Time. These surveys are dedicated to observe the apparent celestial sphere in several days. The usage of an automatic extraction of light curve features is required to work effectively with such amount of data, especially in problems of classification and characterisation of variable sources. In this work, we present the new Python library for extraction of 25 light curve features of variable astronomic sources.

Interstellar planets

The lecture is devoted to the study of the role of gravitational scattering in the evolution of planetary systems. This mechanism explains the origin of the Oort cloud and free asteroids, comets, and planets (ACPs) from the parent star.

Study of possible regularities of the metallic distribution of open cluster stars according to the LAMOST catalog

In this study were discussed the LAMOST catalog opportunities in the statistical studies of the spectra of stars in open star clusters (OSC). We considered the Pleiades and Praesepe clusters. We examined the absolute stellar magnitude — metallicity relationships for the members of these clusters. Contrary to expectations, a noticeable dependence of the metallicity on the absolute magnitude of the stars in the main sequences of the studied clusters was found, which may be associated with systematic errors in measuring the metallicities for visually faint stars.

Cyclicity of variations of the magnetic field of the eclipsing variable AM Leo

Based on the 14-year photometric CCD monitoring of the contact eclipsing variable star AM Leo of type W UMa carried out author from 2007 to 2020 at the telescopes of the Kourovka observatory UrFU, the presence cyclic variations in brightness of the system with a period of 7.6±0.6 years, not associated with the phenomena of eclipses and tidal deformations of the components, as well as low-amplitude cyclic variations of the orbital period with the same value of the oscillation period, were found. It was concluded that the low-amplitule variations of the brightness and period of the system are due to the cyclic changes of the magnetic field of the components of the AM Leo, which manifests itself in a change in the average surface temperature of the overall system shell due to changes in the area of cold or hot spots on the surface of the components, as well as the influence of the Applegate effect on the system period.

Galactic bars: a look at the point of view of action variables

We have translated the results of bar modeling in N-body simulations into the language of action variables JR, Lz and Jz. We used the AGAMA package and the formalism associated with the Steckel potential. Action variables were calculated in the changing non axisymmetric potential of the model at different moments of the bar evolution. We found that at the later stages of the bar evolution, the maximum values of JR are reached at its ends, after which, upon going to the disk, JR decreases monotonically. As for Jz, the maximum values of Jz actually outline the B/PS bulge, the thickest part of the bar. Such a behavior of the action variables can be used for tests to identify the features of the bar of our Galaxy based on GAIA data.

Searching for close approaches of the stars pairs in the galactic disk with Gaia EDR3 data

Using calculations of the orbital motion around the Galactic center we searched for approaching stars on 5 Myr in the past and the future. We provide stars that approached up to 1 pc to each other. Considered process is important for researching the interstellar small bodies origin.

Modernization of the telescope ”Sintez” at the CrAO RAS

In 1978, at the Crimean Astrophysical Observatory, the Sintez telescope, was put into operation. The goal of creating of this experimental telescope was to develop technologies for creating segmented optics, as well as a system for controlling the spatial position of mirrors, including the ability to compensate for turbulence in the Earth’s atmosphere thanks to the fast movements of each mirror along two axes. At the beginning of 2018, a decision was made to restore it with the creation of a new optics and control system. In this work, we present a detailed description of the telescope restoration and upgrade process and the first results.

On the thermal atmospheric escape of π Men c

In this work we present the results of the modeling of exoplanet pi Men c upper atmosphere, produced using the previously developed one-dimensional self-consistent aeronomic model. The model used takes into account the contribution of suprathermal particles, which significantly refines the heating function of the atmosphere. The hight profiles of temperature, velocity and density were obtained, the atmospheric mass-loss rate was calculated. The presence of two hight-scales in the structure of the atmosphere was found: the first corresponds to a relatively dense stationary atmosphere, the second to a more rarefied corona.

In memory of Konstantin Vladislavovich Kholshevnikov

Konstantin Vladislavovich Kolshevnikov (19.01.1939—10.01.2021) was Head of the Department of Celestial Mechanics of St. Petersburg State University, that ruled it for 50 years. He got many important results in science and taught many students who continue his work around the world. Konstantin Vladislavovich created unique courses in celestial mechanics, was engaged in educational work and earned many honorary awards and titles. Long-term chairman of the organizing committee and the jury of the student report competition of the Winter Astronomical School.

X-ray emission fromHerbig stars

The archived X-ray observations of 9 Ae/Be Herbig stars obtained on the XMM-Newton space observatory are analysed for checking the hypotheses of their X-rays formation. An analysis of the dependences of the X-ray radiation characteristics for Herbig stars on the parameters of the stars revealed a close relationship between the magnetic activity and the processes of generation of X-ray radiation from Herbig stars, as well as the possible presence of a non-thermal component of the X-ray spectra.