Even in these instability shock
models, most of the wind is cold
and is a source of X-ray continuum opacity
The massive
winds of O stars are expected to be
optically thick to soft
X-rays…the inner tens of R* may be heavily absorbed: or so it is thought.
The wavelength
dependence of individual lines leads to the expectation that different absorption characteristics will be seen in different lines from a given star.
24 Ĺ
12 Ĺ
Neutral (ISM)
cross section
Wind cross section
models
