X-ray emission from hydrodynamical wind simulations in non-LTE models
Krticka, Jiri; Feldmeier, Achim; Oskinova, Lidia M.; Kubat, Jiri; Hamann, Wolf-Rainer
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.
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