X-ray Observations of Binary and Single
Wolf-Rayet Stars with XMM-Newton and Chandra

S. Skinner$^1$, M. Guedel$^2$, W. Schmutz$^3$,
and S. Zhekov$^4$

1 CASA, Univ. of Colorado, Boulder, CO 80309 USA
2 Paul Scherrer Inst., CH-5232 Villigen PSI, Switz.
3 PMOD, Dorfstr. 33, CH-7260 Davos Dorf, Switz.
4 JILA, Univ. of Colorado, Boulder, CO 80309 USA and Space Res. Inst., Sofia 1000, Bulgaria

We present an overview ofrecent X-ray observations of Wolf-Rayet (WR) stars with
XMM-Newton and Chandra. A new XMM spectrum of
the nearby WN8 + OB binary WR 147 shows hard
heavily absorbed emission, including the Fe
K-alpha line complex, characteristic of colliding wind shock sources. In contrast,
sensitive observations of four of the closest
known single WC (carbon-rich) WR stars have
yielded only non-detections. These results
tentatively suggest that single WC stars are
X-ray quiet. The presence of a companion may
thus be an essential factor in elevating the
X-ray emission of WC + OB stars to detectable

Reference: To appear in: Close Binaries in the 21st Century - New Opportunities and Challenges
(eds. A. Gimenez, E. Guinan, P. Niarchos,
S. Rucinski), Astrophys. and Space Sci. special issue, 2006.
Status: Conference proceedings

Weblink: astro-ph/0511137 (after 7 Nov. 2005)

Comments: 4 pages, 2 figures, 1 table

Email: skinners@casa.colorado.edu