Abundances of Chemical Elements in Open Star Clusters as Indicators of their Nature

Abstract

Applying a compilled catalog, we find that the relative abundances of α-elements in open clusters and in field stars of the thin disk of the Galaxy show different dependencies on metallicity, age and parameters of their Galactic orbits. The distinctions are explained by different nature of open clusters and field stars. We confirm the conclusions, reached earlier from the analysis of the parameters of Galactic orbits, that some clusters may have formed from the impact of metal-poor high-velocity clouds on the interstellar matter of the thin disk. Arguments are also adduced in favor of the formation of metal-rich high-velocity clusters from the interaction of metal-rich intermediate-velocity clouds formed from returning gas of the Galactic “fountain” with the interstellar medium of the thin disk.

Keywords

• stars: red giants
• galaxy: disk
• open clusters: abundances, kinematics