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

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 $\zeta$ 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 ${\tau }_{\ast }$. 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.

29 pages, 8 figures, revised version accepted by ApJ

References in corpus (4)

• The surprising magnetic topology of tauSco: fossil remnant or dynamo output?
• The Effect of Porosity on X-ray Emission Line Profiles from Hot-Star Winds
• High resolution X-ray spectroscopy of bright O type stars
• Wind signatures in the X-ray emission line profiles of the late O supergiant $\zeta$ Orionis

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