Thermal decoupling in W UMa binary systems

Abstract

A study of thermal decoupling in short period near contact binaries is presented. Statistics of well-observed W UMa systems (now including data of EB-type light curve objects) characterize completely A- and W- type objects. W-type systems show a good linear correlation in the thermal decoupling vs. spectral type diagram. The same correlation is valid for the lower border of the distribution of A-type systems, otherwise scattered in an area of large thermal decoupling. These empirical facts are discussed in terms of contact on near contact configurations. A complete version of this paper will be published in Publication Astronomical Soc. of the Pacific.