Globular Clusters of the Galaxy: Chemical Composition vs Kinematics

Abstract

A comprehensive statistical analysis of the relationship between the chemical and spatially kinematic parameters of the globular clusters of the Galaxy has been performed. The data of the author’s compilation catalog contain astrophysical parameters for 157 clusters and the relative abundances of α-elements for 69 clusters. For 121 clusters, the data are supplemented by spatially kinematic parameters taken from the literature. The phenomenon of reddening of horizontal branches of low-metal accreted globular clusters is discussed. We consider the contradiction between the criteria for clusters to belong to the subsystems of the thick disk and the halo in terms of chemical and kinematic properties. It consists in the fact that, regardless of belonging to the galactic subsystems by kinematics, almost all metallic ([Fe/H] >–1.0) clusters are located close to the center and plane of the Galaxy, while among the less metallic of both subsystems there are many distant ones. Differences in the abundances of α-elements in the stellar objects of the Galaxy and the surrounding low-mass dwarf satellite galaxies confirm the well-known conclusion that all globular clusters and field stars of the accreted halo are remnants of galaxies of higher mass than the current environment of the Galaxy. A possible exception is a distant low-metal cluster with low relative abundance of α-elements Rup 106.