Quantitative X-ray Spectroscopy of Massive Stars

L. Oskinova, A. Feldmeier, W.-R. Hamann1

Universität Potsdam, Institut für Physik, Astrophysik


Radiative transfer in a clumped winds is used to describe X-ray emission line profiles observed in the XMM-Newton RGS spectrum of the OI star zeta Puppis. It is shown that this X-ray spectrum can be explained as originating from a multi-temperature collisional plasma located in the wind acceleration zone. The X-rays are attenuated in the clumped stellar wind, which gives characteristic profiles to the emergent lines. We specifically study the NVII emission line in the spectrum of zeta Puppis. Long RGS exposures reveal that the NVII line profile is structured. On the basis of our zeta Puppis atmosphere model, we rule out the presence of NVII in the cool wind component. We suggest that the detailed NVII line structure is due to self-absorption in the hot plasma. Wind clumping also affects the transfer of ionizing radiation in high-mass X-ray binaries (HMXBs). We derive analytical formulae for the ionisation parameter in dependence on the parameters of wind clumping.

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