Something to do with the X-ray Emission of Early-Type Stars

Abstract

The discovery, principally by Abbott and colleagues, of a non-thermal component to the radio emission of a significant fraction of early-type stars suggests an alternative interpretation of the ubiquotous X-ray emission from Wolf-Rayet and OB stellar winds to the usual shock models based on Lucy and White’s work. The radio observations show the presence of relativistic electrons and magnetic fields far out in the wind. The electrons probably also account directly for the X-ray emission because first, Compton scattering of photospheric radiation is likely to produce observable amounts of high-energy radiation and second, the brightest non-thermal radio sources, of both the Wolf-Rayet and OB stars, are among the brightest X-ray sources. The acceleration of these electrons may be achieved by current-sheet acceleration (magnetic reconnection) in both binary systems, as oppositely directed fields are pushed together by colliding winds, and single winds, through the dissipation of turbulence.