X-ray emission from massive stars with magnetic fields

Type Journal Article
Names L. M. Oskinova, W.-R. Hamann, J. P. Cassinelli, J. C. Brown, H. Todt
Publication Astronomische Nachrichten
Volume 332
Issue 9/10
Pages 988
Journal Abbreviation Astronomische Nachrichten
Date December 1, 2011
DOI 10.1002/asna.201111602
ISSN 0004-6337
URL http://adsabs.org/2011AN.332.988O
Library Catalog adslabs.org
Abstract We investigate the connections between the magnetic fields and the X-ray emission from massive stars. Our study shows that the X-ray properties of known strongly magnetic stars are diverse: while some comply to the predictions of the magnetically confined wind model, others do not. We conclude that strong, hard, and variable X-ray emission may be a sufficient attribute of magnetic massive stars, but it is not a necessary one. We address the general properties of X-ray emission from ``normal'' massive stars, especially the long standing mystery about the correlations between the parameters of X-ray emission and fundamental stellar properties. The recent development in stellar structure modeling shows that small-scale surface magnetic fields may be common. We suggest a ``hybrid'' scenario which could explain the X-ray emission from massive stars by a combination of magnetic mechanisms on the surface and shocks in the stellar wind. The magnetic mechanisms and the wind shocks are triggered by convective motions in sub-photospheric layers. This scenario opens the door for a natural explanation of the well established correlation between bolometric and X-ray luminosities. Based on observations obtained with \xmm and \cxo.
Tags Stars: Wolf-Rayet, Techniques: Spectroscopic, X-rays: stars, outflows, stars: magnetic fields, stars: mass-loss, stars: winds
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