Quantitative analysis of resolved X-ray emission line profiles of O stars

Cohen, David H.; Leutenegger, Maurice A.; Townsend, Richard H. D.

Quantitative analysis of resolved X-ray emission line profiles of O stars

Authors

Cohen, David H.

Leutenegger, Maurice A.

Townsend, Richard H. D.

Description

By quantitatively fitting simple emission line profile models that include both atomic opacity and porosity to the Chandra X-ray spectrum of $ζ$ Pup, we are able to explore the trade-offs between reduced mass-loss rates and wind porosity. We find that reducing the mass-loss rate of $ζ$ Pup by roughly a factor of four, to 1.5 \times 10^{-6} M_sun/yr, enables simple non-porous wind models to provide good fits to the data. If, on the other hand, we take the literature mass-loss rate of 6 \times 10^{-6} M_sun/yr, then to produce X-ray line profiles that fit the data, extreme porosity lengths -- of $h_{\infty} \approx 3$ Rstar -- are required. Moreover, these porous models do not provide better fits to the data than the non-porous, low optical depth models. Additionally, such huge porosity lengths do not seem realistic in light of 2-D numerical simulations of the wind instability.
Appearing in "Clumping in Hot Star Winds," eds. Hamann, Feldmeier, & Oskinova, Potsdam: Univ.-Verl., 2007; 3 pages; 5 color figures