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ASCA X-ray observations of the Wolf-Rayet stars HD 193793 and HD 93162

Published online by Cambridge University Press:  07 August 2017

S. Skinner ,
F. Nagase ,
K. Koyama ,
Y. Maeda  and
Y. Tsuboi
S. Skinner
Affiliation:
1Inst of Space & Astronautical Science, 3-1-1 Yoshinodai, Kanagawa 229, Japan
F. Nagase
Affiliation:
2 Department of Physics, Kyoto Univ., Sakyo-ku, Kyoto 606-01, Japan
K. Koyama
Affiliation:
2 Department of Physics, Kyoto Univ., Sakyo-ku, Kyoto 606-01, Japan
Y. Maeda
Affiliation:
2 Department of Physics, Kyoto Univ., Sakyo-ku, Kyoto 606-01, Japan
Y. Tsuboi
Affiliation:
2 Department of Physics, Kyoto Univ., Sakyo-ku, Kyoto 606-01, Japan

Abstract

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The Japan-U.S. satellite ASCA was launched in February 1993 and provides a new capability to obtain high-resolution X-ray spectra of Wolf-Rayet stars in the 0.5 — 10 keV band. We present spectra of the wide binary HD 193793 (WC7+O4-5) obtained three months after periastron with the WC7 star in front, and of the WN7 star HD 93162 in Carina. The spectrum of HD 193793 is heavily absorbed below 2 keV by the WC7 wind and shows a prominent emission line from He-like iron at 6.7 keV. Acceptable fits were obtained using a Raymond-Smith model with kT ≈ 3 keV and non-solar abundances. In contrast, the spectrum of HD 93162 is softer and shows very little emission above ≍2 keV. The relatively low signal-to-noise precludes emission line analysis, and an acceptable spectral fit was obtained using a simple Bremsstrahlung model with kT ≍ 1.6 keV. No significant variability was detected in the X-ray light-curves of either star.

Keywords

stars: Wolf-RayetX-raysindividual: HD 193793, HD 93162
Type
Session VII - Hydrodynamics and high-energy physics of colliding winds
Information
Symposium - International Astronomical Union , Volume 163: Wolf-Rayet Stars: Binaries, Colliding Winds, Evolution , 1995 , pp. 471 - 475
Copyright
Copyright © Kluwer 1995 

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