X-Ray Formation Mechanisms in Massive Binary Systems

Abstract

Massive, hot, luminous stars of types O, early B and WR have strong supersonic radiatively driven winds. Both single and binary early-type stars are known X-ray emitters. According to current understanding of X-ray formation mechanisms in the winds of single and binary early-type massive stars, binaries should be harder and more luminous X-ray sources than single stars. However, recent observational studies with the X-ray satellites XMM-Newton and Chandra show that, on average, X-ray properties of single and binary early-type massive stars are not very different. I review the mechanisms of X-ray production in early- type stars with emphasis on binary systems and discuss a possible explanation to this discrepancy.