Variability in X-ray line ratios in helium-like ions of massive stars: the wind-driven case. (arXiv:1903.06745v1 [astro-ph.SR])

Variability in X-ray line ratios in helium-like ions of massive stars: the wind-driven case. (arXiv:1903.06745v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Ignace_R/0/1/0/all/0/1">R. Ignace</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Damrau_Z/0/1/0/all/0/1">Z. Damrau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hole_K/0/1/0/all/0/1">K. T. Hole</a>

High spectral resolution and long exposure times are providing unprecedented
levels of data quality of massive stars at X-ray wavelengths. A key diagnostic
of the X-ray emitting plasma are the fir lines for He-like triplets. In
particular, owing to radiative pumping effects, the
forbidden-to-intercombination line luminosity ratio, R=f/i, can be used to
determine the proximity of the hot plasma to the UV-bright photospheres of
massive stars. Moreover, the era of large observing programs additionally
allows for investigation of line variability. This contribution is the second
to explore how variability in the line ratio can provide new diagnostic
information about distributed X-rays in a massive star wind. While there are
many ways to drive variability in the line ratio, we use variable mass loss as
an illustrative example. The f/i ratio can be significantly modulated owing to
evolving wind properties. We evaluate how variable mass loss might bias
measures of f/i.

High spectral resolution and long exposure times are providing unprecedented
levels of data quality of massive stars at X-ray wavelengths. A key diagnostic
of the X-ray emitting plasma are the fir lines for He-like triplets. In
particular, owing to radiative pumping effects, the
forbidden-to-intercombination line luminosity ratio, R=f/i, can be used to
determine the proximity of the hot plasma to the UV-bright photospheres of
massive stars. Moreover, the era of large observing programs additionally
allows for investigation of line variability. This contribution is the second
to explore how variability in the line ratio can provide new diagnostic
information about distributed X-rays in a massive star wind. While there are
many ways to drive variability in the line ratio, we use variable mass loss as
an illustrative example. The f/i ratio can be significantly modulated owing to
evolving wind properties. We evaluate how variable mass loss might bias
measures of f/i.

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