Quantitative X-ray spectroscopy of O stars

L.M. Oskinova, W.-R. Hamann, A. Feldmeier

Potsdam University, Germany

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 N VII emission line in the spectrum of Zeta Pup.
Long RGS exposures reveal that the N VII line profile is structured. On
the basis of our Zeta Pup atmosphere model, we rule out the presence of N
VII in the cool wind component. We suggest that the detailed N VII 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.

Reference: in Proc. MSSL Workshop no.2 "High resolution X-ray spectroscopy: towards XEUS and Con-X", MSSL, 27 - 28 March 2006
Status: Conference proceedings

Weblink: astro-ph/0605560


Email: lida@astro.physik.uni-potsdam.de