Subdwarf B Binaries from the SPY Project

Abstract

In the course of our search for double degenerate binaries as potential progenitors of type Ia supernovae with the ESO VLT (ESO - SN Ia progenitor survey - SPY), several sdB binaries were discovered. We report on the analysis of six radial velocity variable sdB stars from the SPY project. Radial velocity curves have been measured. Effective temperatures, surface gravities and helium abundances are determined, as well as metal abundances. We highlight some strong abundance anomalies.