RGS Abundance Measurement of Wolf-Rayet Stellar Wind

The WolfRayet system HD 193793 is a wide binary classified as WC7 + O45with an orbital period of 7.94 years. HD 193793 emits the thin thermal Xray emission from the colliding wind shock. The Xray spectrum is alsoheavily absorbed below 2 keV by the WolfRayet wind. We thus proposeRGS/XMM observation of HD 193793 in November 2001, 10 months after periastron passage. With the highspectroscopic capability of RGS, we expect to clearly detect neon Klines and Kedge in the spectrum, which allow us tomeasure neon abundance for the first time. The neon abundance in WR winds ishelpful to constrain the chemical evolution of massive stars and crucial to ourunderstanding of the Galaxy, the ISM and the cosmicrays. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]