Linear Radii of 51 Red Giants in Galactic Clusters

Abstract

The linear radii of 51 red giants in the galactic clusters Hyades, Praesepe, M37, M67, NGC 7789, and Stock 2 have been determined using the Barnes-Evans surface brightness relation and cluster-fitting distances. Masses were obtained for the 28 stars for which surface gravities were obtainable from published DDO photometry. The results indicate that revisions of the bolometric correction and DDO surface gravity calibrations are desirable. The mass determination appears to be a sensitive indicator of cluster membership requiring only photometry.