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Kinematics of star complexes within the Sgr-Car armстатья
- Авторы: Glushkova E.V., Uglova I.M.
- Сборник: Dynamical Studies of Star Clusters and Galaxies, Joint European and National Astronomy Meeting for 1998 (JENAM98)
- Год издания: 1998
- Место издания: ESA Publ. Division, c/o ESTEC Noordwijk, The Netherlands
- Первая страница: 173
- Аннотация: Kinematics of open star clusters (OCL) was studied in the region of A, B, and C star complexes isolated by Avedisova (1989, Astrofizika V.30, P.140) in Sgr-Car arm. As raw data, we involved the absolute proper motions of OCL derived by the stars from the 4-Million Star Catalog of Positions and Proper Motions compiled in Sternberg Institute. The typical accuracy of these proper motions am ounts to 0.005 arcsec/yr. The distances to the clusters were taken from the catalog by Dambis (1998, in press). On the first stage, the kinematic models were calculated for three cases: (i) expansion of the complex from its center at a constant velocity in the galactic plane; (ii) the symmetric case of the complex compression, and (iii) its rotation around the center, also in the plane of Galaxy. The curves V_l(l), V_l(r), V_r(l), and V_r(r) were calculated for the objects under study (here, V_l stands for the tangential velocity component along the galactic longitude, V_r denotes the radial velocity, l is the galactic longitude, and r is the heliocentric distance. For each level of the accuracy of the input data, we calculated the minimum velocity of expansion (compression, rotation), at which the effect could ever be noticed. Our analysis of the residual velocities of 19 OCL has shown that complex A is static. This conclusion was confirmed by the behavior of 11 cepheids belonging to this complex. The study of 24 OCL in complex B provided an evidence of the fact that the complex is apparently expanding at the velocity of about 25 km/s. The investigation of the tangential velocities of 15 cepheids from this complex confirmed this fact. For complex C, where we studied 32 OCL and the radial velocities of 13 cepheids, it was found to compress at about 15 km/s.
- Добавил в систему: Глушкова Елена Вячеславовна