Contact Binaries of the Galactic Disk: Comparison of the Baade's Window and Open Cluster Samples

Abstract

The paper attempts to integrate the available data for contact binaries of the disk population in a deep Galactic eld and in old open clusters. The two basic data sets consist of 98 systems in the volumelimited 3 kpc subsample of contact binaries detected by the OGLE microlensing project toward Baades window and of 63 members of 11 old open clusters (CL). Supplementary data on the intrinsically (BW 3 ) bright, but spatially rare, long-period binaries are provided by 238 systems in the BW sample to the distance of 5 kpc