X-ray Emission in Wolf-Rayet Stars: XMM Reveals the Shocking Truth

The ROSAT allsky survey detected Xray emission from single WolfRayet (WR)stars and WR binaries. Because of their weaker emission, no spectra of single WRstars presently exist that are of sufficient quality to test theories of theirXray emission. We propose to utilize the large effective area of XMM to obtainthe first highquality spectrum of a single WR star. Current theories attributethe Xray emission of single stars to strong shocks that form in their winds asa result of radiative instabilities. If such theories are correct, then the XMMspectra should show only cooler plasma with temperatures below 1 keV. If hotterplasma is detected then radiative shock models will be ruled out. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]