| Type |
Journal Article |
| Names |
R. Ignace, W. L. Waldron, J. P. Cassinelli, A. E. Burke |
| Publication |
The Astrophysical Journal |
| Volume |
750 |
| Issue |
1 |
| Pages |
40 |
| Date |
May 1, 2012 |
| URL |
http://adsabs.harvard.edu/abs/2012ApJ...750...40I |
| Library Catalog |
NASA ADS |
| Abstract |
The consequences of structured flows continue to be a pressing topic in
relating spectral data to physical processes occurring in massive star
winds. In a preceding paper, our group reported on hydrodynamic
simulations of hypersonic flow past a rigid spherical clump to explore
the structure of bow shocks that can form around wind clumps. Here we
report on profiles of emission lines that arise from such bow shock
morphologies. To compute emission line profiles, we adopt a
two-component flow structure of wind and clumps using two "beta"
velocity laws. While individual bow shocks tend to generate
double-horned emission line profiles, a group of bow shocks can lead to
line profiles with a range of shapes with blueshifted peak emission that
depends on the degree of X-ray photoabsorption by the interclump wind
medium, the number of clump structures in the flow, and the radial
distribution of the clumps. Using the two beta law prescription, the
theoretical emission measure and temperature distribution throughout the
wind can be derived. The emission measure tends to be power law, and the
temperature distribution is broad in terms of wind velocity. Although
restricted to the case of adiabatic cooling, our models highlight the
influence of bow shock effects for hot plasma temperature and emission
measure distributions in stellar winds and their impact on X-ray line
profile shapes. Previous models have focused on geometrical
considerations of the clumps and their distribution in the wind. Our
results represent the first time that the temperature distribution of
wind clump structures are explicitly and self-consistently accounted for
in modeling X-ray line profile shapes for massive stars. |
| Tags |
X-rays: stars, outflows, stars: early-type, stars: mass-loss, stars: massive, stars: winds |