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Vol 100, No 4 (2023)
Articles
3D Numerical Model of the Envelope of a Hot Exoplanet Based on Spherical Coordinates
Abstract
A new 3D parallel numerical code in spherical coordinates has been developed to study the stellar wind flow around hot Jupiter. The peculiarity of the spherical coordinate system in the vicinity of the poles is overcome by using a ternary spherical grid, which is a composite grid consisting of three separate sectors. The numerical model of multicomponent magnetohydrodynamics, developed earlier for Cartesian coordinates, has been transferred to the new model. The results of a numerical calculation of the structure of an extended envelope of a quasi-open type for the case of a super-Alfvenian flow around a hot Jupiter are presented. We showed that the spatial resolution of the grid is sufficient for a self-consistent calculation of the structure of the atmosphere of a hot Jupiter. This allows further use of the new model for 3D aeronomic calculations.
305-318
New Value of Apsidal Motion Velocity and Physical Parameters of the Triple Eclipsing System AS Cam
Abstract
Applying a new approach to the measurement of the rate of apsidal motion in the system AS Cam (P=3.43d, V=8.58m, e=0.17, Sp B7.5 V+B9.0 V), we obtained the value ω˙obs= 0.38°/yr, which is not as large as results of earlier measurements differs from the theoretical value for synchronized motion ω˙theor = 0.44°/yr. Previous generally accepted value was three times lower. Physical parameters of the components have been refined: T1=12980±150 K, M1=3.21±0.03M⊙, R1=2.46±0.01R⊙, T2=10850±100 K, M2 = 2.32 ± 0.03M⊙, R2=1.84±0.01R⊙. For the first time, a reliable orbit and physical parameters of the invisible satellite, the third body in the system, have been determined: P=2.21 yr, ω = 88°, e=0.70, M3sini=0.97±0.01M⊙.
319-335
Star Structure of the Northern Part of the Orion Sword Region
Abstract
According to the data of the Gaia DR3 catalogs, the belonging of the stars of group 189 ([1]), located in the northern part of the Orion Sword region, to the open star cluster (OSC) NGC 1977 was analyzed. To do this, the revision of the stellar composition of the northern part of the Orion Sword region (around the center of the OSC NGC 1977) was carried out using proper motions (PM) and parallaxes. At the same time, a part of the OSC NGC 1981, also located in the region under consideration, was captured. The presented catalog (n = 1041) includes candidate stars both in NGC 1977 and in NGC 1981 with the corresponding probabilities. The status of the stars of group 189 (Oricat 2836 and Oricat 2914) suggests their contribution to the X-ray radiation detected in this region. The question of the possible gravitational coupling of the NGC 1977–NGC 1981 pair is considered.
336-392