X-ray spectral diagnostics of activity in massive starsReport as inadecuate



 X-ray spectral diagnostics of activity in massive stars


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X-rays give direct evidence of instabilities, time-variable structure, and shock heating in the winds of O stars. The observed broad X-ray emission lines provide information about the kinematics of shock-heated wind plasma, enabling us to test wind-shock models. And their shapes provide information about wind absorption, and thus about the wind mass-loss rates. Mass-loss rates determined from X-ray line profiles are not sensitive to density-squared clumping effects, and indicate mass-loss rate reductions of factors of 3 to 6 over traditional diagnostics that suffer from density-squared effects. Broad-band X-ray spectral energy distributions also provide mass-loss rate information via soft X-ray absorption signatures. In some cases, the degree of wind absorption is so high that the hardening of the X-ray SED can be quite significant. We discuss these results as applied to the early O stars zeta Pup O4 If, 9 Sgr O4 Vf, and HD 93129A O2 If*.



Author: David H. Cohen; Emma E. Wollman; Maurice A. Leutenegger

Source: https://archive.org/







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