Paper detail

A study of contact binaries with large temperature differencies between components

We present an extensive analysis of new light and radial-velocity (RV) curves, as well as high-quality broadening-function (BF) profiles of twelve binary systems for which a contact configuration with large temperature differencies between components has been reported in the literature. We find that six systems (V1010 Oph, WZ Cyg, VV Cet, DO Cas, FS Lup, V747 Cen) have near-contact configurations. For the remaining systems (CX Vir, FT Lup, BV Eri, FO Hya, CN And, BX And), our solutions of the new observations once again converge in a contact configuration with large temperature differencies between the components. However, the bright regions discovered in the BFs for V747 Cen, CX Vir, FT Lup, BV Eri, FO Hya, and CN And, and further attributed to hot spots, shed new light on the physical processes taking place between the components and imply the possibility that the contact configurations obtained from light- and RV-curve modelling are a spurious result.