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Evidence for the importance of resonance scattering in X-ray emission line profiles of the O star $ζ$ Puppis

Maurice A. Leutenegger·Stanley P. Owocki·Steven M. Kahn·Frits B. S. Paerels
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Abstract

We fit the Doppler profiles of the He-like triplet complexes of \ion{O}{7} and \ion{N}{6} in the X-ray spectrum of the O star $ζ$ Puppis, using XMM-Newton RGS data collected over $\sim 400$ ks of exposure. We find that they cannot be well fit if the resonance and intercombination lines are constrained to have the same profile shape. However, a significantly better fit is achieved with a model incorporating the effects of resonance scattering, which causes the resonance line to become more symmetric than the intercombination line for a given characteristic continuum optical depth $τ_*$. We discuss the plausibility of this hypothesis, as well as its significance for our understanding of Doppler profiles of X-ray emission lines in O stars.

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Maurice A. Leutenegger, Stanley P. Owocki, Steven M. Kahn, Frits B. S. Paerels. 2007-03-03. Evidence for the importance of resonance scattering in X-ray emission line profiles of the O star $ζ$ Puppis. https://doi.org/10.1086/512031

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