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The First Light Curve Solutions and Period Study of BQ Ari
Akyuz, A.; Aksaker, N.; Poro, A. +14 more
The first analysis of the photometric observation in BVR filters of a W UMa type binary system BQ Ari was performed. Light curve analysis was performed using Wilson-Devinney (W-D) code combined with a Monte Carlo (MC) simulation to determine its photometric and geometric elements and their uncertainties. These results show that BQ Ari is a contact…
Study of Close Stellar Encounters with the Solar System Based on Data from the Gaia EDR3 Catalogue
Bobylev, V. V.; Bajkova, A. T.
We have studied stellar candidates for close (within 1 pc) encounters with the Solar system. For all of the stars under consideration the kinematic characteristics have been taken from the Gaia EDR3 catalogue. The parameters of the encounters of these stars with the Solar system have been calculated using three methods: (1) the linear one, (2) by …
Spectroscopic Redshift Determination for a Sample of Distant Quasars Detected by the SRG Observatory Based on RTT-150 Observations. II
Irtuganov, E. N.; Bikmaev, I. F.; Gilfanov, M. R. +16 more
Results of the spectroscopic observations at the 1.5-m Russian-Turkish telescope for another group of 12 X-ray sources discovered by the eROSITA telescope onboard the SRG space observatory and identified by the SRGz machine learning system as candidates for distant X-ray quasars are presented. Ten objects have been confirmed as quasars at redshift…
Analysis of Selected Runaway Stars in the Orion Nebula Based on Data from the Gaia EDR3 Catalogue
Bobylev, V. V.; Bajkova, A. T.
We have performed Monte Carlo simulations of the trajectories of several runaway stars using their parallaxes and proper motions from the Gaia EDR3 catalogue. We have confirmed the hypothesis that the stars AE Aur and $µ$ Col are a product of the multiple system breakup ${∼}2.5$ Myr ago and the Orion Trapezium may be the parent cluster for t…
Study of the Influence of an Evolving Galactic Potential on the Orbital Properties of 152 Globular Clusters with Data from the Gaia EDR3 Catalogue
Bobylev, V. V.; Bajkova, A. T.; Smirnov, A. A.
We have studied the influence of an evolving gravitational potential of the Milky Way Galaxy on the orbital motion of 152 globular clusters with proper motions from the Gaia EDR3 catalogue and mean distances from Baumgardt and Vasiliev (2021). To construct a semicosmological evolving model potential with changing masses and sizes of the Galactic c…
Kinematic Properties of the GAIA EDR3 Catalogue
Tsvetkov, A. S.
We have obtained a solution of the Ogorodnikov-Milne stellar-kinematics equations based on the material of the entire Gaia EDR3 star catalogue containing 1.8 billion objects. In view of the insufficient accuracy of individual trigonometric parallaxes, we have also obtained an analogous solution based on a sub-catalogue of selected 98 million stars…
Changes in the Period of SU Sct, a Population II Cepheid
Berdnikov, L. N.; Pastukhova, E. N.
The reduction of all the available photometry for the Cepheid SU Sct has allowed its $O-C$ diagram spanning a time interval of 60 years to be constructed. Six abrupt changes in the period have been detected. The pulsation stability test proposed by Lombard and Koen (1993) has confirmed that the changes in the period are real. The absolute magnitud…
To the Globular Cluster Classification Problem. Calculating the Concentration of Stars for 26 Clusters
Nuritdinov, S. N.; Tatjibaev, I. U.; Rastorguev, A. S.
In view of the absence of a satisfactory solution to the globular cluster (GC) classification problem, we have searched for a physical parameter that admits of the GC classification and finding empirical dependences on observed physical characteristics. For this purpose, we have considered a model of the apparent density in GCs with three free par…
Spectroscopic Variability of the Compact Planetary Nebula Hb 12
Arkhipova, V. P.; Esipov, V. F.; Ikonnikova, N. P. +5 more
We present the results of our new low-resolution spectroscopic observations of the young compact planetary nebula Hb 12 performed in 2011-2020 with SAI MSU telescopes. We have measured the intensities of more than 50 nebular emission lines in the spectral range $λ$3687-9532, detected interstellar absorption features, and conducted a search for abs…
Changes in the Period of V420 Cen, a W Vir-Type Cepheid
Berdnikov, L. N.
The reduction of all the available photometry for the Cepheid V420 Cen has allowed its $O-C$ diagram spanning a time interval of 131 years to be constructed. The data obtained provide evidence for the existence of large random fluctuations in the period ($\varepsilon/P≈ 0.021$). Fitting the $O-C$ residuals by a cubic parabola has made it possible …