Search Publications
Oxygen Atom Escape from the Martian Atmosphere during Proton Auroral Events
Shematovich, V. I.; Kalinicheva, E. S.
We present the model calculation results of the atomic oxygen loss rate from the Martian atmosphere induced by precipitation of high-energy protons and hydrogen atoms (H/H+) from the solar wind plasma. Penetration of energetic protons and hydrogen atoms from the solar wind plasma to the upper atmosphere of Mars at altitudes of 100-250 k…
New Expansion Rate Estimate of the Scorpius-Centaurus Association Based on T Tauri Stars from the Gaia DR2 Catalog
Bobylev, V. V.; Baykova, A. T.
The kinematic properties of the Scorpius-Centaurus association were studied using spatial velocities of approximately 700 young T Tauri stars. Their proper motions and trigonometric parallaxes were selected by Zari et al. from the Gaia DR2 catalog, and radial velocities were taken from various sources. The linear expansion coefficient's new estima…
Binary Star Population with Common Proper Motion in Gaia DR2
Kovaleva, D. A.; Malkov, O. Yu.; Sapozhnikov, S. A. +1 more
<sec id="ASec1"><title>Abstract—We describe a homogeneous catalog compilation of common proper motion stars based on Gaia DR2. A preliminary list of all pairs of stars within the radius of 100 pc around the Sun with a separation less than a parsec was compiled. Also, a subset of comoving pairs, wide binary stars, was selected. The clus…
Kinematic Properties of Young Intermediate- and Low-Mass Stars from the Gaia DR2 Catalogue
Bobylev, V. V.; Bajkova, A. T.
We have studied the kinematic properties of young pre-main-sequence stars. We have selected these stars based on data from the Gaia DR2 catalogue by invoking a number of photometric infrared surveys. Using 4564 stars with parallax errors less than 20%, we have found the following parameters of the angular velocity of Galactic rotation: km s-1…
Solar System Encounters with Open Star Clusters
Vereshchagin, S. V.; Chupina, N. V.; Sizova, M. D. +1 more
The time and minimum distances of approaches were calculated more than 100 open star clusters (OSCs) near the Solar System over the past 5 Myr. It was shown that the closest proximity of the centers of the OSCs to the Solar System usually exceeded 60 pc. The Hyades cluster approached the Solar System at ~25 pc. The effect of such encounters on the…
Physical and Chemical Properties of Galactic Global Clusters with Various Origins Identified from the Gaia DR2 Data
Marsakov, V. A.; Koval', V. V.; Gozha, M. L.
The differences in the relationships between the physical parameters and the chemical-element abundances in accreted globular star clusters and those formed inside the Galaxy have been investigated. The information on the supposed formation sites of the clusters based on the Gaia DR2 data is borrowed from the literature. Those sources estimate the…
Apex and Kinematical Structure of Castor and Ursa Major Moving Stellar Groups
Elsanhoury, W. H.
Based on space velocity components UVW and using a recent dataset for Castor and Ursa Major moving groups, we compute the apex position with two methods. Classical convergent procedures give (Acp, Dcp) = (807830, -172598; Castor, 298334, -346405; UMa) for Castor and Ursa Major groups. According to the AD-map method we deduce …
First Space and Kinematical Analysis of Newly Discovered Southern UFMGs Clusters with Gaia
Elsanhoury, W. H.
The work on the kinematical parameters and spatial shape structure have been performed with Gaia DR2 astrometry data of the new recently southern discovered open clusters UFMG 1, UFMG 2, and UFMG 3 in the vicinity (∼1.3 degrees radius) of the rarely studied NGC 5999. The apexes positions with AD-diagram method are computed for about 107, 168, 98, …
Narrow-Line SY1 NGC 4748 in X-Rays: Detailed Case-Study
Vasylenko, A.; Fedorova, E.; Del Popolo, A.
We analyze all the available X-ray data in order to monitor the narrow-line Seyfert 1 galaxy NGC 4748, namely XMM-Newton (EPIC and OM), INTEGRAL (ISGRI and JEM-X), and SWIFT (BAT and XRT) data to study both the wide-band 0.5-195 keV spectrum and light curves in details. To this aim, we use the autocorrelation analysis of the light curves, modeling…