X-ray emission from hydrodynamical wind simulations in non-LTE models

0372640 - ASÚ 2012 RIV GB eng C - Konferenční příspěvek (zahraniční konf.)
Krtička, J. - Feldmeier, A. - Oskinova, L.M. - Kubát, Jiří - Hamann, W.-R.
X-ray emission from hydrodynamical wind simulations in non-LTE models.
Active OB stars: structure, evolution, mass loss, and critical limits. Cambridge: Cambridge University Press, 2011 - (Neiner, C.), s. 614-615. IAU Symposium Proceedings Series, IAU S272. ISBN 978-0-521-19840-0. ISSN 1743-9213.
[Symposium of the International Astronomical Union /272./. Paris (FR), 19.07.2010-23.07.2010]
Grant CEP: GA ČR GA205/08/0003
Výzkumný záměr: CEZ:AV0Z10030501
Klíčová slova: stars winds * outflows * hydrodynamics
Kód oboru RIV: BN - Astronomie a nebeská mechanika, astrofyzika

Massive hot stars are strong sources of X-ray emission originating in their winds. Although hydrodynamical wind simulations that are able to predict this X-ray emission are available, the inclusion of X-rays in stationary wind models is usually based on crude approximations. To improve this we use results from time-dependent hydrodynamical simulations of the line-driven wind instability to derive an analytical approximation of X-ray emission in the stellar wind. We use this approximation in our non-LTE wind models and find that an improved inclusion of X-rays leads to a better agreement between model ionization fractions and those derived from observations. Furthermore, the slope of the Lx-L relation is in better agreement with observations, albeit the X-ray luminosity is underestimated by a factor of three. We propose that a possible solution for this discrepancy is connected with the wind porosity.
Trvalý link: http://hdl.handle.net/11104/0205905