Search Publications
MLS120126:042313+212951—A New Eclipsing Cataclysmic Variable in the Period Gap
Kolbin, A. I.; Aitov, V. N.; Kotov, S. S. +2 more
We have analyzed our photometric and spectroscopic observations of the new eclipsing cataclysmic variable MLS120126:042313+212951. We have found the system's orbital period $P=0.1034329$ day (${≈}2.48$ h) corresponding to the gap $2\lesssim P\lesssim 3$ h in the distribution of cataclysmic variables. A Doppler tomogram in the H$β$ line demonstrate…
Orbits of Visual Double Stars from P. Couteau's Catalogue Determined with Gaia DR2 and Gaia EDR3 Data
Kisser, A. E.; Krechet, V. G.
The orbits of ten stars discovered by P. Couteau have been determined for the first time: COU 99, 357, 610, 850, 1346, 1531, 1642, 1752, 1845, and 2459. For two of them (COU 850 and 1752) an arc of more than half a revolution is covered by observations; the orbits of the remaining stars have been determined from short arcs ($5^{\circ}{-}50^{\circ}…
Observation of the Second LIGO/Virgo Event Connected with a Binary Neutron Star Merger S190425z in the Gamma-Ray Range
Minaev, P. Yu.; Pozanenko, A. S.; Grebenev, S. A. +1 more
The results of observations of the gravitational-wave (GW) event S190425z recorded by the LIGO/Virgo detectors with the anti-coincidence shield (ACS) of the SPI gamma-ray spectrometer onboard the INTEGRAL observatory are presented. With a high probability (>99%) it was associated with a neutron star (NS) merger in a close binary system. This is…
Galactic Rotation Parameters Based on Stars from Active Star-Forming Regions with Data from the Gaia DR2 Catalogue
Bobylev, V. V.; Bajkova, A. T.; Krisanova, O. I.
We have studied a sample of more than 25 000 young stars with proper motions and trigonometric parallaxes from the Gaia DR2 catalogue. The relative errors of their parallaxes do not exceed 10$%$. The selection of stars belonging to active star-forming regions was made by Marton et al. based on data from the Gaia DR2 catalogue by invoking infrared …
Influence of Collisions with Hydrogen on Titanium Abundance Determinations in Cool Stars
Sitnova, T. M.; Yakovleva, S. A.; Belyaev, A. K. +1 more
The possibility of solving the problem of a discrepancy in the non-LTE abundances from Ti I and Ti II lines in metal-poor stars is investigated by applying accurate data to take into account the collisions with hydrogen atoms. For this purpose, we have calculated for the first time the rate coefficients for bound-bound transitions in inelastic col…
Ice Permafrost ``Oases'' Close to Martian Equator: Planet Neutron Mapping Based on Data of FREND Instrument Onboard TGO Orbiter of Russian-European ExoMars Mission
Mitrofanov, I. G.; Golovin, D. V.; Litvak, M. L. +8 more
We present the first results of Mars neutron sounding by FREND instrument onboard ESA's Trace Gas Orbiter data analysis. Neutron flux mapping is performed with high spatial resolution, which allows to match epithermal neutron flux variation with relief's geomorphological structures. Local regions with suppressed neutron flux indicate the presence …
Study of the Galactic Rotation Based on Masers and Radio Stars with VLBI Measurements of Their Parallaxes
Bobylev, V. V.; Bajkova, A. T.; Krisanova, O. I.
Based on published data, we have produced a sample of 256 radio sources whose trigonometric parallaxes and proper motions were measured by VLBI. This sample contains Galactic masers associated with massive protostars and stars in active star-forming regions. It also includes young low-mass stars from the Gould Belt region whose radio observations …
Analysis of Close Stellar Encounters with the Solar System
Bobylev, V. V.; Bajkova, A. T.
We consider 36 candidates for close (within 1 pc) encounters with the Solar system. These stars have been selected in accordance with the results of an analysis of their motion obtained by various authors. For most stars from this list the kinematic characteristics have been taken from the Gaia DR2 catalogue. The parameters of the encounters of th…
A Model of the Dust Envelope of the Carbon Mira Star V CrB from Photometry, Infrared Spectroscopy, and Speckle Polarimetry
Safonov, B. S.; Tatarnikov, A. M.; Shenavrin, V. I. +2 more
$UBVJHKLM$ photometry for the carbon Mira star V CrB are presented. The infrared observations were carried out in the time interval 1989-2018, while the $U$, $B$, and $V$ data were obtained in 2001-2014. The light and color curves are analyzed. The pulsation period of V CrB has been found to be $355\overset{\textrm{d}}{.}2$ in the infrared $JHKLM$…
Evolutionary Status of the Ap Stars HD 110066 and HD 153882
Romanovskaya, A. M.; Ryabchikova, T. A.; Shulyak, D. V.
We present the results of our determination of the fundamental atmospheric parameters for the magnetic chemically peculiar Ap stars HD 110066 (AX CVn) and HD 153882 (V451 Her). The determination of the atmospheric parameters ($T_{\textrm{eff}}$, $\textrm{log}{g}$, $R/R_{\odot}$, and $L/L_{\odot}$) is based on a self-consistent analysis of high-res…