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Colliding wind X-rays in γ Velorum (WC8+O9I)

Published online by Cambridge University Press:  07 August 2017

Allan J. Willis ,
Hans Schild  and
Ian R. Stevens
Allan J. Willis
Affiliation:
Department of Physics and Astronomy, University College London Gower Street, London WC1E 6BT, U.K.
Hans Schild
Affiliation:
Institute of Astronomy, ETH-Zentrum, CH-8092 Zürich, Switzerland
Ian R. Stevens
Affiliation:
School of Physics and Space Research, University of Birmingham Edgbaston, Birmingham B15 2TT, U.K.

Abstract

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Our ROSAT observations of γ Velorum obtained over several binary cycles reveal substantial, and repeatable phase-dependent X-ray (0.1—2.5 keV) variations. The derived X-ray light-curve shows a 4 x increase in flux at phase ∼ 0.5, which is shown to arise in shocked gas formed in the collison of the two stellar winds, viewed through a cavity in the WC8 wind with an observed opening angle of ∼ 50°. This colliding-wind X-ray emission has Lx ≥ 1032 ergs−1 and kT ≥ 2 keV. Our 2-D hydrodynamical models of the system predict copious X-ray emission from the wind-collision region, at a level and spectrum similar to that observed. Harder (1—10 kev) X-ray observations with the ASCA satellite are being sought to provide improved constraints on the luminosity, spectrum and absorption of the wind-collision emission, and the complex theoretical models involved.

Keywords

stars: Wolf-RayetX-rayscolliding winds
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. 476 - 480
Copyright
Copyright © Kluwer 1995 

References

Lucy, L.B., White, R.L. 1982, ApJ 241, 300 Google Scholar
Moffat, A.F.J., Vogt, N., Paquin, G., Lamontagne, R., Barrera, L.H. 1986, AJ 91, 1386 Google Scholar
Owocki, S., Castor, J.I., Rybicki, G.R. 1988, ApJ 355, 914 CrossRefGoogle Scholar
Pollock, A.M.T. 1987, ApJ 320, 283 Google Scholar
Shafer, R.A., Haberl, F., Arnaud, K.A., Tennant, A.F. 1991, XSPEC: an X-ray spectral fitting package, ESA TM-09 Google Scholar
St-Louis, N., Willis, A.J., Stevens, I.R. 1993, ApJ 415, 298 Google Scholar
Stevens, I.R., Blondin, J.M., Pollock, A.M.T. 1992, ApJ 386, 265 CrossRefGoogle Scholar
White, R.L., Long, K.S. 1986, ApJ 310, 882 Google Scholar
Willis, A.J., Schild, H., Howarth, I.D., Stevens, I.R. 1994a, in: Moffat, A.F.J., Owocki, S.P., Fullerton, A.W. & St-Louis, N. (eds.), Instability and Variability of Hot-Star Winds (Dordrecht: Kluwer), Ap Space Sci. in press Google Scholar
Willis, A.J., Schild, H., Stevens, I.R. 1994b, A&A submitted Google Scholar