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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 

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