On OB-type close binary stars

A compilation of masses, radii, effective temperatures and luminosities is presented for the components of 31 binary systems with spectral types in the range O-B5. Comparisons of the data on the 16 detached systems in the sample with main-sequence models for individual stars provides further observational confirmation of the recent (1981-86) conclusions from theoretical studies that convective overshooting and stellar-wind mass loss must be included in evolutionary models. Of the remaining systems, eight are in semi-detached configurations and seven are in (mostly) marginal-contact states. Comparisons of these observational data with evolutionary models for binary stars are made and it is concluded that all the systems in this sample have evolved or will evolve through a case A mass-transfer process. (author)