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Article
XMM-Newton observations of the nitrogen-rich Wolf-Rayet star WR 1.
Astronomy & Astrophysics (2003)
  • R. Ignace, University of Wisconsin - Madison
  • L. M. Oskinova
  • J. C. Brown, University of Glasgow
Abstract

We present XMM-Newton results for the X-ray spectrum from the N-richWolf-Rayet (WR) star WR1. The EPIC instrument was used to obtain a medium-resolution spectrum. The following features characterize this spectrum: ( a) significant emission "bumps" appear that are coincident with the wavelengths of typical strong lines, such as MgXI, SiXIII, and SXV; (b) little emission is detected above 4 keV, in contrast to recent reports of a hard component in the stars WR 6 and WR 110 which are of similar subtype; and ( c) evidence for sulfur K-edge absorption at about 2.6 keV, which could only arise from absorption of X-rays by the ambient stellar wind. The lack of hard emission in our dataset is suggestive that WR 1 may truly be a single star, thus representing the first detailed X-ray spectrum that isolates the WR wind alone ( in contrast to colliding wind zones). Although the properties of the S-edge are not well-constrained by our data, it does appear to be real, and its detection indicates that at least some of the hot gas in WR 1 must reside interior to the radius of optical depth unity for the total absorptive opacity at the energy of the edge.

Publication Date
September, 2003
Publisher Statement
Copyright © ESO 2003.
Citation Information
R. Ignace, L. M. Oskinova, and J. C. Brown. "XMM-Newton observations of the nitrogen-rich Wolf-Rayet star WR 1." Astronomy & Astrophysics 408.1 (2003): 353-361.
DOI: 10.1051/0004-6361:20031024
Available at: http://works.bepress.com/richard_ignace/20