Astronomičeskij žurnal
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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Том 102, № 8 (2025)
Articles
Search for the Possible Members of the Open Cluster NGC 3532 with Poor Astrometric Solutions of Gaia DR3
Аннотация
We performed star counts in the region of the open cluster NGC 3532. The ranges of trigonometric parallaxes and proper motions containing all the stars of the cluster were determined using the stars with 5- and 6-parameter Gaia DR3 solutions. The estimated radius of the cluster was and the number of cluster stars was . We estimate the number of stars with poor astrometric solutions that may be members of the cluster. For this purpose, we analyze the surface density distribution of stars with two-parameter Gaia DR3 solutions, stars with the parameter , and stars with large relative errors of trigonometric parallaxes in the vicinity of the cluster. We are looking for stars that fall within the area of the color-magnitude diagram occupied by probable members of the NGC 3532 cluster from the Hant-Reffert sample. The radial surface density profile plotted with such stars shows the concentration of stars toward the cluster center. An analysis of the profile yields an estimate of stars that may be cluster members. Among these stars, there may be a significant number of unresolved binary and multiple systems.
Astronomičeskij žurnal. 2025;102(8):641-652
641-652
Effect of luminosity outbursts on the amount of pebbles and ice mantles in protoplanetary disks
Аннотация
Dust growth is one of the key processes leading to planet formation in protoplanetary disks. Centimeter-sized dust grains — pebbles — are essential for the formation of planetesimals through streaming instability and play a crucial role in the formation of protoplanetary cores, giant planets, and the enrichment of their atmospheres with chemical elements. This study investigates the impact of luminosity outbursts on the amount of pebbles and icy mantles in a protoplanetary disk. We perform global simulations of the formation and evolution of a self-gravitating, viscous protoplanetary disk using the two-dimensional thin-disk hydrodynamic code FEOSAD, which self-consistently produces luminosity outbursts. The model includes thermal balance, dust evolution and its interaction with gas, the development of magnetorotational instability, adsorption and desorption of four volatile species (H2O, CO2, CH4, and CO), and the feedback of icy mantles on the fragmentation properties of dust aggregates. Our results show that luminosity outbursts have a stronger impact on the snowlines of CO2, CH4, and CO than on the water snowline. This is because the H2O snowline resides in a region dominated by viscous heating during the early stages of disk evolution, whereas the snowlines of the other molecules lie in regions where stellar irradiation dominates the thermal structure, making them more sensitive to temperature variations induced by the outbursts. Nevertheless, luminosity outbursts lead to a twofold reduction in the total amount of pebbles in the disk due to the fragmentation of dust aggregates into monomers following the loss of water ice, which acts as a binding agent. The reformation of pebbles occurs over several thousand years after the outburst, primarily through collisional coagulation. The characteristic timescales for pebble recovery significantly exceed the freezing timescales of water ice. The desorption of icy mantles occurs in a highly non-axisymmetric and intrinsically two-dimensional region of the disk, which is linked to the formation of spiral substructures during the early evolution of a gravitationally unstable disk.
Astronomičeskij žurnal. 2025;102(8):653-670
653-670
Aspects of Optimization of the Transit Light Curve of the Binary System with a Single Minimum in the Eccentricity Components
Аннотация
A high-precision algorithm for interpreting transit light curves in the model of an eclipsing classical binary star-exoplanet system has been improved for interpretation moving from the variables “eccentricity (e)–periastron longitude (ω)” to the eccentricity components (ecosω,e sinω).The possibilities of interpretation by eccentricity components have been studied. It has been shown that the dependence of the minimum’s
shape on e sinω alone is clearly expressed for small values of e and weakens with increasing e. The linear correlation between the radius value, which is characteristic of any values of e, is shown.
Astronomičeskij žurnal. 2025;102(8):671-682
671-682
Absolute parameters and apsidal rotation of the eclipsing system V501 Mon
Аннотация
Our photoelectric measurements over the past 30 years and a new solution of the radial velocity curve of the eclipsing star with an elliptical orbit V501 Mon (A8 + F2) allowed us to determine with high accuracy all the main parameters of the system: T1 = 7380 ± 60 K, M1 = 1.66 ± 0.03 M☉, R1 = 1.90 ± 0.02 R☉, T2 = 6920 ± 30 K, M2 = 1.47 ± 0.02 M☉, R2 = 1.58 ± 0.01 R☉. The photometric parallax determined in the study coincides with the Gaia value π = 0.00103″ within the error limits. For the first time, the apsidal rotation velocity ω̇_obs = 0.022°/year was accurately measured, which, within the error limits, matches the theoretical value: ω̇_theor = 0.024°/year, 70 % of this value being a relativistic contribution. The system possibly satisfies the condition of synchronism between rotational and orbital angular momenta. The age of the stars was determined to be 0.95 billion years. The main component is probably a pulsating variable star of the δ Scuti type (DSCT).
Astronomičeskij žurnal. 2025;102(8):683-706
683-706
Tayler instability of magnetic field as possible reason for the period changes in Ap star 56 Ari
Аннотация
The physical mechanism responsible for the photometric period changes in chemically peculiar star 56 Ari was searched. It was previously shown that rate of the star’s period increase is few orders of magnitude larger than the rates expected from the evolutionary changes of the angular momentum or due to magnetic braking. Also no secular changes were detected in the surface structure or visibility of chemical spots which are responsible for the rotational modulation of stellar brightness. We hypothesise that period changes in 56 Ari are caused by the drift of surface magnetic and associated abundance structures as a result of the kink-type (Tayler) instability of the background magnetic field in the radiative zone of the star. Results of the numerical simulation presented in the paper yield growth and drift rates of the most rapidly developing non-axisymmetric mode of the instability, consistent with the observed rate of period changes in 56 Ari. The surface geometry of the 56 Ari magnetic field is also reproduces in the calculations. The proposed mechanism may also be used to explain the character of period changes in other Ap/Bp stars demonstrating such an effect.
Astronomičeskij žurnal. 2025;102(8):707-717
707-717
Characteristics of Non-Kolmogorov Atmospheric Optical Turbulence for High-Resolution Astronomical Observations
Аннотация
This paper is devoted to the study of atmospheric optical turbulence using both measurements within the atmospheric surface layer and modeling data for the entire optically active atmosphere. Estimates of the structure characteristics of Kolmogorov and non-Kolmogorov atmospheric optical turbulence are presented. Approaches for calculations of atmospheric coherence lengths, including the Fried parameter, the Bump length, and the coherence lengths of non-Kolmogorov optical turbulence of turbulent air temperature fluctuations sensitive to deformations of the energy spectrum are discussed. Estimates of the daytime atmospheric angular resolution (seeing) at the Large Solar Vacuum Telescope site are given. Developed methodological foundations for calculating characteristics of optical turbulence and atmospheric angular resolution can be applied to other astronomical observatories (both solar and stellar).
Astronomičeskij žurnal. 2025;102(8):718-727
718-727
Average temporal profiles of solar flare microwave emission: morphology and application
Аннотация
Both solar and stellar average time profiles of emission demonstrate general laws of evolution of such complex and diverse phenomenon as flare. Empirically obtained average profiles for events with simple dynamic allow us both to analyse the emission mechanisms of solar and stellar flares and to help to divide complex events into discrete acts of energy release. Microwave emission is of particular interest, since it can reflect the precipitation dynamics of accelerated electrons. For the reconstruction of average time profiles, 116 events were selected from the Siberian Radioheliograph observations in the 3–24 GHz range. These profiles demonstrated a simple time structure and a broadband gyrosynchrotron spectrum of non-thermal nature. The wide spectral range allowed to divide emission into emission of optically thick and optically thin sources. The time profiles that describe the emission from different regions of the flare loop were summed within the respective spectral band, after which for each event, normalization and time scaling were applied. The average time profiles were obtained as the median value for each time bin (step). As a result, it was shown that the microwave average time profiles for the microwave optically thick and thin sources are identical for a solar flare with simple dynamics. This indicates the dominance of accelerated electron precipitation processes in the emission of such events. Also, the dominance of non-thermal processes for this type of event is confirmed by a comparison with the results of a solar flare dynamics modelling in the 304 Å line obtained in works of other authors and an analysis of the dynamics of microwave emission during the decay phase. Analytical functions were obtained that describe the rise and decay phases of microwave emission of a solar flare. The use of analytical functions in combination with the average time profile for the analysis of the 03 February 2022 event showed the possibility of using this method to separate the acts of energy release associated with the precipitation of accelerated electrons. The obtained average time profiles, as well as analytical functions describing the behaviour of simple solar flare microwave emission, can be used to analyse both the emission of solar events in the microwave range and to study the processes occurring during stellar flares.
Astronomičeskij žurnal. 2025;102(8):728-742
728-742