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Volume 102, Nº 11 (2025)
Articles
REGISTRATION OF BURSTS OF GRAVITY-GRADIENT AND NEUTRINO BACKGROUND BY UNDERGROUND DETECTORS
Resumo
The problem of registration of collapsing stars in the Galaxy is considered using two instruments: the optoacoustic gravitational detector OGRAN and the neutrino telescope BUST, located in the underground laboratories of the BNO INR RAS. An algorithm for joint data processing on the experience of registration of the SN1987A event is presented. The proposed method is illustrated by the current output signals of these instruments.
Astronomy Reports. 2025;102(11):963-974
963-974
THE PLACE OF THE RADCLIFFE WAVE IN THE LOCAL SYSTEM
Resumo
A review of publications devoted to the study of the characteristics of the Radcliffe wave is given. The advent of mass measurements of radial velocities of stars has recently led to a number of interesting results obtained from the analysis of spatial velocities of stars and open star clusters. An important place in the work is given to issues related to the clarification of the direct or indirect influence of magnetic fields on the process of formation of the Radcliffe wave. The hypothesis of Parker instability of the galactic magnetic field as one of the reasons for the formation of wave-type inhomogeneities in the galactic disk is discussed.
Astronomy Reports. 2025;102(11):975-988
975-988
COMPACT SOURCES OF OH MASER EMISSION IN THE STAR-FORMING REGION CEP A
Resumo
The paper analyzes archival data of the RadioAstron ground-space interferometer project concerning observations of radiation in the OH hydroxyl lines (1665 MHz and 1667 MHz transitions) in the Cep A source. The observations were carried out on January 7, 2013. The duration of the observation session was about one hour. Ground-based radio telescopes at the Zelenchuk Observatory (Special Astrophysical Observatory of the Russian Academy of Sciences, North Caucasus, Russian Federation), in Yevpatoria (Crimea, Russian Federation) and at the Torun Astronomy Center (Republic of Poland) participated in the observations. No interferometric response was detected at the ground-space bases. Several compact sources with angular sizes from 10 to 20 milliarcseconds were detected at the base between the radio telescopes in Torun and at the Zelenchuk Observatory. These angular sizes correspond to linear sizes of 7.5–15 astronomical units (AU). It is shown that the detected compact sources are distributed over a region of 750–1500 AU.
Astronomy Reports. 2025;102(11):989-994
989-994
STUDY OF THE MIGRATION OF EARTH-LIKE PLANETS IN PLANETESIMAL DISKS AND THE FORMATION OF DEBRIS DISKS
Resumo
The aim of this study is to investigate the interaction of Earth-mass planets with a disk of planetesimals. It is shown that an Earth-like planet, initially located near the inner boundary of the planetesimal disk, migrates inside the disk. The magnitude of penetration of the planet into the disk is a random value determined by the angular momentum distribution of planetesimals approaching the planet. However, at a certain stage, the direction of the planet's migration always changes, and the planet returns to the inner boundary of the disk. During such reversible migration, the planet perturbs the orbits of planetesimals and increases their relative velocities in the region of the disk where it was during its migration. The relative velocities of planetesimals increase to values sufficient for their fragmentation during collisions. Our estimates show that after the passage of an Earth-mass planet through the outer planetesimal disk, the average relative velocities in the main part of the disk increase to values sufficient for the fragmentation of monolithic basaltic planetesimals ~40 km in size. Thus, the interaction of even a small planet (of the order of Earth's mass) with a planetesimal disk can lead to the formation of dust particles observed in outer debris disks.
Astronomy Reports. 2025;102(11):995-1005
995-1005
PULSAR B1237+25 AT 111 MHz: AVERAGE PROFILE, MODE SWITCHING, NULLINGS, MICROSTRUCTURE
Resumo
An analysis of observations of the pulsar B1237+25 at a frequency of 111 MHz is presented. The observations were carried out with the Large In-Phase Antenna (LPA) of the Pushchino Radio Astronomical Observatory of P.N. Lebedev Physical Institute. A new component was detected in the average profile in the central region of the emission. This component with a half-width of 1.6 ms is observed against the background of a more extended component with a half-width of 7 ms. This new component of the average profile at a frequency of 111 MHz manifests itself in all modes of the pulsar radio emission: quiet-normal (QN), flare-normal (FN) and in the abnormal mode (AB), and in the abnormal mode it was also detected by other observers at other frequencies. The drift of subpulses is observed in the normal mode of emission only in the extreme (first and last) components. The normal mode is interrupted by nullings and transitions to the abnormal mode AB. In the AB mode, the structure of the activity zones at the edge of the outer cone is destroyed, the distance between the inner and outer cones increases almost twice, and the distance between the inner cone and the central region decreases. Analysis of our data showed that the components of the outer and inner cones of the average profile are formed by the ordinary mode of radio emission (O-mode) and constitute a single cone emission of the pulsar. The central components of the average profile (wide and narrow) are formed by the extraordinary mode of emission (X-mode). Estimates of the height of the emission from the central region (X-mode) and the cone emission (O-mode) are obtained: 80 km and 370 km, respectively. A microstructure with a submicrosecond time scale of τµ ≤ 0.5μs was discovered. Such a time scale corresponds well to the characteristic time of spark discharge development in the polar cap. For this value of τµ, the vacuum gap height should be hp ≤ 750 cm. Based on the steepness of the trailing edge of an individual pulse at the longitude of the first component, a limit was obtained on the value of the γ factor of the relativistic secondary plasma: γ ≥ 260. The analysis showed that in 88% of cases, the normal mode (N) is realized, and in 81% of them — the QN mode and only in 19% the FN mode. The AB mode is only 12%. The dependence of the distance between the components of the outer and inner cones of radiation on the frequency is the same and corresponds to a power law with an index of −0.16.
Astronomy Reports. 2025;102(11):1006–1021
1006–1021
MEASUREMENT OF RADIO EMISSION SCATTERING PARAMETERS AT THE FREQUENCY 1650 MHz IN THE DIRECTION OF PULSAR B1937+21 WITH GROUND-SPACE INTERFEROMETER RADIOASTRON
Resumo
As part of the Early Science Program of the RadioAstron project, the millisecond pulsar B1937+21 was observed in October 2012. The total duration of the experiment supported by eight ground-based radio telescopes was about three hours. The radiation in both circular polarizations in the frequency band of 1644–1676 MHz was recorded. Characteristic time and frequency scales of scintillation caused by the scattering on the interstellar plasma density fluctuations were measured: Δdiff = 275.2 ± 0.1 s and ΔV diff = 580 ± 30 kHz. The angular diameter of the scattering disk, θH = 0.32 ± 0.03 mas, have been estimated from the drop-off of the amplitude of the interferometric response at the ground-space baselines. The dependence of the visibility amplitude on the delay shows two scattering time scales: τsc1 = 110 ± 30 ns and τsc2 = 750 ± 100 ns, which indicates an ellipse-like scattering disc with an axis ratio of 2.6:1. The drift of the visibility maximum on the residual interference frequency that was observed at the intercontinental baselines can be explained by atmospheric effects, the dominant contribution being the additional phase shift in the troposphere above European stations.
Astronomy Reports. 2025;102(11):1022-1035
1022-1035
X-RAY BINARIES WITH Be STARS
Resumo
The basic properties of Be stars and X-ray binary systems containing these stars are considered. In the vast majority of these systems the Be stars' companions are neutron stars accreting matter from the decretion disk of a rapidly rotating Be star. The observed properties of such systems are studied within the framework of the hypothesis that the reason for the high rotational velocity of Be stars is the large initial angular momentum of the protostellar cloud, and during the evolution of the star on the main sequence, the angular momentum is transferred from the interior of the star to the surface. The work uses the results of calculations performed earlier by the authors of the evolution of rapidly rotating Be stars, taking into account their stellar wind, which carries away the angular momentum of the outer layers of the star. Based on the rates of rotational mass loss by Be stars through the decretion disk, obtained in these calculations, it is estimated which part of the disk material is captured by the neutron star in observed X-ray binaries with Be stars. For systems with short orbital periods of about 30 days, the maximum value of this part can exceed 0.01. At the same time, for observed systems, this part significantly (sometimes by more than 2 orders of magnitude) exceeds the fraction of the Be star's stellar wind captured by the neutron star.
Astronomy Reports. 2025;102(11):1036-1052
1036-1052