Astronomy Reports
ISSN (print): 0004-6299
Media registration certificate: № 0110223 от 08.02.1993
Founder: Russian Academy of Sciences (RAS), Institute of Astronomy of the Russian Academy of Sciences
Editor-in-Chief: Dmitry V. Bisikalo, ORCID iD: 0000-0003-2025-5564
Number of issues per year: 12
Indexation:
- RISC,
- Higher Attestation Commission list,
- RISC core,
- RSCI,
- White List (2nd level)
Astronomičeskij žurnal is an international peer reviewed journal that publishes original papers on astronomical topics, including theoretical and observational astrophysics, physics of the Sun, planetary astrophysics, radio astronomy, stellar astronomy, celestial mechanics, and astronomy methods and instrumentation.
- Recognized for excellence since 1924
- Coverage includes astronomy, including theoretical and observational astrophysics, physics of the Sun, planetary astrophysics, radioastronomy, stellar astronomy, celestial mechanics, and astronomy methods and instrumentation
- Publishes chronicles and proceedings of international conferences
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Vol 102, No 12 (2025)
Articles
THREE MODELS OF THE GRAVITATIONAL POTENTIAL OF THE MILKY WAY
Abstract
The parameters of the axisymmetric model of the gravitational potential of the Galaxy have been refined. The basic curve of the Galaxy’s rotation in the distance interval R ∼ 0 – 190 kpc was constructed using the velocities of masers, classical Cepheids, Red Clump stars, Blue Horizontal Branch stars, halo stars, globular clusters, and dwarf satellite galaxies of the Milky Way. The rotation curve was selected in such a way that there would be no dominant burst of circular velocities in the central (R < 2 kpc) region of the Galaxy. As a result, two two-component models of the galactic potential were constructed, including contributions from the disk and halo of invisible matter, as well as a three-component model with a small-mass bulge added in advance. Such models can be useful in studying the long-term orbital evolution of stars, open and globular star clusters in the central (R < 4 kpc) region of the Galaxy. A self-consistency test of the constructed models was carried out by comparing their rotation curves with a set of model curves that were generated using the Illustris TNG50 software package.
Astronomy Reports. 2025;102(12):1055–1067
1055–1067
INTERSTELLAR MEDIUM IN EXTREMELY HIGH STAR FORMATION REGIONS: A PROSPECT OF OBSERVATIONS ON THE “MILLIMETRON” SPACE OBSERVATORY
Abstract
High star-formation rate and emission from the active galactic nucleus can significantly transform the interstellar medium. In ultraluminous infrared galaxies, in which the star-formation rate reaches thousands of solar masses per year, the gas and dust are considerably affected by the ionizing radiation, cosmic rays and shockwaves, that can be about a factor of 100–1000 larger than typical values in quiet star-forming galaxies. In these conditions, the emissivity of the gas and dust changes: in dense gas, high ionic and molecular transitions get excited, while dust grains are heated to high temperatures. In this work, we analyse the possibilities for studying the interstellar medium in extreme conditions of ultra-luminous infrared galaxies at redshifts 0–3, utilising the atomic and molecular lines, and dust continuum in far infrared range 100–500μ m. We discuss the prospect of observations using the instruments of the Millimetron Space Observatory.
Astronomy Reports. 2025;102(12):1068–1086
1068–1086
ABOUT STARK BROADENING OF RECOMBINATION RADIO LINES IN THE ORION A NEBULA
Abstract
In order to study the Stark broadening of recombination radio lines in Orion A at a wavelength of 13.5 mm, observations of the H93γ, H94γ, H95γ and H65α lines were carried out at the RT22 (FIAN) radio telescope. An excess of the Stark broadening from the theoretical predictions was found for levels with the main quantum number (n) in the range of 93–95 with Δn = 2, 3. The recombination radio line H82β was also observed together with the H145(12) and H152(14) lines, the latter also showed an excess of the Stark broadening from the theoretical predictions. It is shown that the Stark broadening data of different frequencies can be consistently described in units of velocities by the dependence ~n4–4.5 in the range of n values from 70 to 174. For the first time, the density gradient estimates in this HII region were obtained using the Stark broadening. The electron density of the nebula center turned out to be ≈2 times higher than at a distance of 2–3′ from the center.
Astronomy Reports. 2025;102(12):1087–1094
1087–1094
THE INFLUENCE OF VARIATIONS OF ELEMENTAL COMPOSITION OF A GAS ON THE MOLECULAR KINETICS
Abstract
The low efficiency of metal mixing in the interstellar gas preserves their spatial inhomogeneities for longer times. In this work, we study how the variations in the elemental composition affects the chemical evolution of the molecular gas, that cools down behind the supernovae shock fronts. We perform numerical simulations of the non-equilibrium chemical kinetics of a Lagrangian gas element experiencing the shockwaves travelling at 5–15 km/s velocities. We vary the chemical abundances of carbon and oxygen in range ±0.3 dex from the values typical for the ISM. We find significant differences in fractions of several molecular species, disproportionate with the variations in the abundances of the corresponding chemical elements. While these differences are remarkably higher than the variations of the given element abundances. We investigate how these changes in the molecular fractions depend on the properties of the gas, as well as on the external effects: gas density, ultraviolet flux, cosmic ray ionization rate and extinction. We find, for instance, that variations of oxygen abundance for δ[O/H] ~ ±0.3 dex of the Solar value, modify the water molecule fraction already by ~ 3–50 times. The differences are the most prominent for extinction values AV ~ 0.3–3. We discuss the importance of these findings for chemical kinetics in star-forming regions.
Astronomy Reports. 2025;102(12):1095–1108
1095–1108
OH MASER EMISSION IN THE REGION OF ACTIVE STAR FORMATION W51M
Abstract
The results of a study of maser emission in the lines OH 1665 and 1667 MHz in the W51M star formation region are presented. The observations were carried out in 2022 and 2024 at the Large Radio Telescope in Nancay (France). The results of a study of the evolution of the flux density and the degree of circular polarization of individual spectral features are presented. Spatial identification of spectral features is carried out. It was found that the degree of linear polarization mL of the five strongest features (55.92, 57.18, 57.72, 58.27 and 59.5 km/s) in the 1665 MHz line does not exceed 5%. The vector of the transverse magnetic field for these features is oriented within the angle 19.6° – 39.2°. Thus, it can be assumed that there is a spatially organized large-scale magnetic field in W51M (e1 and e2).
Astronomy Reports. 2025;102(12):1109–1120
1109–1120
SU UMa-TYPE DWARF NOVA MASTER OT J212624.16+253827.2 IN PERIOD GAP: ORBITAL PERIOD AND NEGATIVE SUPERHUMPS
Abstract
The results of the analysis of photometric observations of the long-period SU UMa-type dwarf nova MASTER OT J212624.16+253827.2 are presented based on the data of ZTF, ATLAS, GAIA, ASAS-SN obtained in 2018–2023 (HJD 245 6772–246 0568) and the Crimean Astrophysical Observatory obtained in 2023–2024 (HJD 246 0199–246 0576) at different stages of outburst activity. We found that this observation interval is notable for variations in the dwarf nova supercycle and cycle, equal to 146–184 days and 12–37 days, respectively. For the first time, we determined the orbital period equal to 0.0865044(2) days, which dominated in the 2018–2023 (HJD 245 8228–245 8836) quiescence and the period of negative superhumps 0.083–0.084 days, which dominated in 2023–2024 (HJD 246 0199–246 0576) quiescence. The estimated mass ratio of the system components is 0.21(2).
Astronomy Reports. 2025;102(12):1121–1131
1121–1131
RESULTS OF MONITORING OF MAGNETAR SGR 1935+2154 FOR 2021–2024
Abstract
This paper presents the results of observations of the magnetar SGR 1935+2154 at a frequency of 111 MHz with the BSA LPI radio telescope in the period from April 2021 to November 2024. To search for both periodic and single pulses, data from six frequency channels with a time resolution of 0.1 s, which are recorded in the reception band of (110.25 ± 1.25) MHz, were used. During data processing for the specified period, an estimate of the upper limit, 250 mJy, of radio emission of the magnetar SGR 1935+2154 at a frequency of 111 MHz was obtained.
Astronomy Reports. 2025;102(12):1132–1136
1132–1136
RRAT SEARCH ON DECLINATIONS FROM +42° TO +55° WITH A NEURAL NETWORK
Abstract
In an area 3 300 square degrees a search for pulse dispersed signals using a neural network has been carried out. When processing observations over an interval of six months, the pulses of fifteen known pulsars were found, as well as three new rotating radio transients (RRATs). For new sources, their main characteristics are given. The dispersion measure of transient and pulse half-width are in the ranges of 7.2–59.9 pc/cm3 and 20–300 ms. An RRAT search scheme has been developed to detect pulses with a signal-to-noise ratio (S/N) below the threshold required for reliable detection.
Astronomy Reports. 2025;102(12):1137–1146
1137–1146
ACTIVITY CYCLES OF SOLAR-TYPE STARS WITH SUPERFLARES
Abstract
Based on data of solar-type stars with superflares from the archive of the TESS space mission a study of the cyclical nature of their magnetic activity was carried out. Of the 711 stars with superflares selected according to papers by Tu (Zuo-Lin Tu) and co-authors the KWS photometric archive of ground-based observations contains data for 401 stars (of which there are at least 300 brightness measurements for 331 stars). From this list of objects manifestations of cyclical activity were detected in 115 objects. The relations between the values of rotation periods and cycles of activity of objects have been studied. It is found that the corresponding diagrams indicate that the cyclic properties of the studied G-dwarfs with superflares coincide with other stars. This allows us to conclude that the mechanism of activity is likely to be common. The slope of dependence obtained by joint approximation by dominant cycles for G-dwarfs with superflares and other objects is equal to 1.03 ± 0.03, which corresponds to the available literature data. Probably, two sequences with the same slope which may correspond to analogues of the Schwabe solar cycles with duration of 2–3 years duration are distinguished in the diagram.
Astronomy Reports. 2025;102(12):1147–1156
1147–1156
METHOD FOR DETERMINING THE PARAMETERS OF A RING-LIKE STRUCTURE FROM THE VISIBILITY FUNCTION SHAPE
Abstract
Black hole images obtained by very long baseline interferometry (VLBI) by the Event Horizon Telescope are a new tool for testing general relativity in super-strong gravitational fields. These images demonstrated a ring-like structure which can be explained as the black hole shadow image. To date, there are no reliable methods for determining the parameters of these ring-like structures, such as diameter, width, and asymmetry. In this paper, an algorithm for determining black hole image parameters is proposed using a Gaussian asymmetric ring as an example. Using the proposed method, the diameter and asymmetry parameters of the image of a supermassive black hole in the galaxy M87 were estimated based on observational data obtained by the Event Horizon Telescope group.
Astronomy Reports. 2025;102(12):1157–1171
1157–1171
DISTANT TRANS-NEPTUNIAN OBJECTS IN THE SOLAR SYSTEM WITH ADDITIONAL OUTER PLANETS
Abstract
Numerical simulations of the evolution of the Solar system consisting at the initial stage of five, six, seven and eight outer planets, as well as a self-gravitating planetesimal disk, were carried out. The dynamical evolution of planetary systems was studied over a time interval of 4 Gyr. In most cases of numerical simulations, either the destruction of planetary systems or the transition of planets to orbits significantly different from modern orbits occurred. However, a number of successful variants were found in which the configuration of the orbits of the outer planets after 4 Gyr was close to the present Solar system. The ejection of additional planets can occur at all stages of the evolution of the Solar system. In the variant with eight planets, a case of an additional planet remaining in a distant trans-Neptunian orbit with a perihelion distance of q = 120 au was found. Despite the great diversity of evolutionary paths of systems with additional planets, distant trans-Neptunian objects were registered in all successful variants. A trend towards an increase in the number of surviving distant trans-Neptunian objects with an increase in the number of additional planets was noted.
Astronomy Reports. 2025;102(12):1172–1179
1172–1179
CHARACTERISTICS OF THE ENSEMBLE OF CLOSE POTENTIALLY HAZARDOUS ASTEROIDS
Abstract
Optimization of search (detection) of near-Earth asteroids (NEAs) is of practical interest. Almost all NEAs larger than ~700 m (>90%) are known. However, the modern interpretation of the NEA detection problem includes the requirement for the exhaustive detection of asteroids larger than 10 m. So far, there are no detection systems that meet this requirement, either in the world or in Russia, but work is underway to create them. This paper considers some astronomical justifications for choosing an effective strategy for searching for NEAs, especially for asteroids that can enter near-Earth space, i.e. approach the Earth at a distance of less than 1.5 million km. In this work, asteroids that will enter the near-Earth space within the next 100 years are classified as close potentially hazardous asteroids (CPHA). Practically significant distributions of asteroids are constructed — by celestial sphere, by brightness and by angular velocity. Comparison of distributions for the ensemble of all NEAs larger than 10 m (according to the NEOMOD model) and for the ensemble of CPHAs showed that the distributions of CPHAs over the celestial sphere and by angular velocity differ from such distributions for all NEAs. In particular, the mean angular velocities of CPHA in a large range of distances (0.1–0.5 au) are much (an order of magnitude) lower than for all NEAs located at the same distances. It is important to take into account the features of the CPHA distributions when developing a strategy for their detection program.
Astronomy Reports. 2025;102(12):1180–1192
1180–1192
CHANGES IN THE ASTROCLIMATE OF TADJIKISTAN'S HIGH MOUNTAIN OBSERVATORIES
Abstract
The paper examines some parameters of the astroclimate of two high mountain observatories in Tajikistan: Sanglok and Shorbulak. Long-term variations and seasonal features of total cloud cover and deposited water vapor are analyzed according to the ERA5 atmospheric reanalysis data. Estimates of the statistical significance of trends since 1980 have been made. The results of water vapor precipitation and surface wind velocity measurements at Sanglok Observatory from 2024–2025 are presented.
Astronomy Reports. 2025;102(12):1193–1202
1193–1202