New Insights into the X-ray Sources in Hot Star Winds

Nathan A. Miller, Joseph P. Cassinelli (University of Wisconsin-Madison), Wayne L. Waldron (Emergent-IT), Joseph J. MacFarlane (Prism Computational Sciences) David H. Cohen (Swarthmore College, Prism Computational Sciences )


Abstract

The HETG X-ray emission-line spectra of hot stars have revealed a suprising diversity of characteristics. Although all the early-type stars we have observed have shown extremely broad emission lines ($\approx$ 500-1000 km s-1 HWHM), only $\zeta$ Puppis has shown the line-centroid blue-shifting expected from wind optical depth effects. Using helium-like ion line diagnostics, it appears that the hardest X-rays in both $\zeta$ Pup and $\zeta$ Ori originate close to their photospheres, a region where it would be difficult to form strong shocks. The hard X-ray emission from $\delta$ Ori originates from a distance roughly corresponding to its close companion star, so binary wind effects are discussed as a possible additional X-ray source.

CATEGORY: NORMAL STARS AND WHITE DWARFS



 

Himel Ghosh
2001-08-02