Search Publications
On the Motion of Multiple Stars in the Pleiades Based on Gaia DR2
Danilov, V. M.
We estimated a number of parameters for small groups of stars in the open Pleiades star cluster using Gaia DR2 coordinate and proper motion data for stars in the region of radius d = 2.5° relative to the center of the cluster on the celestial sphere. We selected 36 wide pairs of stars with magnitudes mG < 15m and velocitie…
On the Motion of Stars in the Pleiades According to Gaia DR2 Data
Danilov, V. M.; Seleznev, A. F.
—Several parameters of the Pleiades cluster were estimated. We used Gaia DR2 data on the coordinates, proper motions, and radial velocities of stars in regions with radius d° =2.5° and size 60° × 60° around the cluster center. Based on data on stars with magnitudes mG ≤ 18m, we constructed a map and profile of the density, lu…
Globular Clusters Lost by the Sagittarius Dwarf Spheroidal Galaxy
Sharina, M. E.; Arakelyan, N. R.; Pilipenko, S. V.
—In this work a search was carried out for globular clusters belonging to the Sagittarius (Sgr) tidal stream using the analysis of spatial positions, radial velocities relative to the Galactic Standard of Rest (VGSR), proper motions and ratio of "age–metallicity" ([Fe/H]) for globular clusters and for stars in the tidal stream. As a res…
Estimation of the Gould Belt Scale Height from T Tauri Type Stars in the Gaia DR2 Catalog
Bobylev, V. V.; Bajkova, A. T.
—We analyze the spatial and kinematic properties of a large sample of young T Tauri type stars in a 500 pc radius solar neighborhood, closely related to the Gould belt. The following parameters of the exponential density distribution have been determined: the average
Contribution of a Non-Thermal Component to the X-Ray Emission of OB Stars
Kholtygin, A. F.; Ryspaeva, E. B.
—In the paper the possibility of the presence of a non-thermal component described by a power law spectrum in the X-ray spectra of OB stars is investigated. The low-resolution spectra of 101 OB stars obtained using the EPIC camera on the XMM satellite are analyzed. It is concluded that the contribution of the non-thermal component of X-ray emissio…
Study of Star-Forming Regions in the Peculiar Galaxies NGC 660, NGC 1512, NGC 4395, and NGC 4618
Smirnova, K. I.; Wiebe, D. S.; Moiseev, A. V. +1 more
—The star-forming regions (SFRs) in the peculiar galaxies NGC 660, NGC 1512, NGC 4395 and NGC 4618 are studied. The relationships between such characteristics of star forming regions as UV, near- and far-IR fluxes, as well as in the Hα and HI lines, surface brightness in these ranges, and the scatter of the radial velocities of ionized and neutral…
Relative Motion in the Hierarchical Triple System ADS48 on the Basis of Gaia DR2 and 26-Inch Refractor of Pulkovo Observatory Data
Zhuchkov, R. Ya.; Kiyaeva, O. V.; Izmailov, I. S.
—According to the exact positions and proper motions of the three components of the star ADS48 from Gaia DR2, their parallax and radial velocities for the epoch 2015.5 the instantaneous relative positions and motions of the components were determined. Only from the Gaia DR2 observations, the family of orbits of the AB pair was calculated by the me…
Physical and Dynamical Parameters of the Triple Stellar System: HIP 109951
Docobo, J. A.; Hussein, A. M.; Mardini, M. K. +5 more
The precise determination of the physical and dynamical parameters of the HIP 109951 triple star system (WDS J22161-0705AB) which is formed by the A, Ba, and Bb components are presented. The binary nature of component B was recently confirmed by studying the radial velocities. The analysis of the system follows Al-Wardat's complex method for analy…
Unity and Diversity of Yellow Hypergiants Family
Klochkova, V. G.
We present the results of long-term spectral monitoring of yellow hypergiants (YHGs) of northern hemisphere with a R ≥ 60 000 resolution. The spectra of these F–G stars of extreme luminosity, compactly located at the top of the Hertzsprung–Russell diagram revealed a variety of spectral features: various types of Hα profile, the presence (or absenc…
Kinematics of Open Star Clusters Based on the Data of the New Version of the "Homogeneous Catalog of Open Cluster Parameters"
Loktin, A. V.; Popova, M. E.
We investigate some aspects of Galactic disc kinematics based on the data on open clusters from the current version of "The Homogeneous Catalog of the Main Parameters of Open Star Clusters" and from Gaia DR2. Based on the radial velocity and proper motion data for the clusters we determine the angular velocity of the Sun in the Galaxy as Ω0