Metallicities and α-Abundancesin Open Clusters

Abstract

Galactic open clusters exhibit a range of properties that make them valuable probes of stellar and galactic chemical evolution. Metallicities have been determined for open clusters through a variety of photometric and spectroscopic techniques. The status of available data is reviewed and an overview of what these metallicities reveal about Galactic chemical evolution is given. Although many fewer determinations of elemental abundances in open clusters have been made, they serve as useful indicators of nucleosynthesis in previous generations. The available data suggest that the open clusters present a fairly uniform population similar to that of the disk field stars in the solar neighborhood, even to ages of 10 Gyr. There are intriguing indications that the outermost clusters in the disk deviate from the overall abundance gradient and show enhanced α-elements.