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arXiv · 1912.08748

Quantitative Modeling of the UV Line Profiles of Magnetic Massive Stars

Christiana Erba·Veronique Petit·Alexandre David-Uraz·Alex Fullerton
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Abstract

Recent spectropolarimetric surveys (MiMeS, BOB) have revealed that approximately 7% of massive stars host stable, surface dipolar magnetic fields with strengths on the order of kG. These fields channel the dense radiatively driven stellar wind into a circumstellar magnetosphere. Wind-sensitive UV spectral lines can probe the density and velocity structure of massive star magnetospheres, providing insight into wind-field interactions. To date, large-scale magnetohydrodynamic modeling of this phenomenon has been limited by the associated computational cost. Our analysis, using the Analytic Dynamical Magnetosphere model, solves this problem by applying a simple analytic prescription to efficiently calculate synthetic UV spectral lines. It can therefore be applied in the context of a larger parameter study to derive the wind properties for the population of known magnetic O stars. We also present the latest UV spectra of the magnetic O star NGC 1624-2 obtained with HST/COS, which test the limits of our models and suggest a particularly complex magnetospheric structure for this archetypal object.

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Christiana Erba, Veronique Petit, Alexandre David-Uraz, Alex Fullerton. 2019-12-18. Quantitative Modeling of the UV Line Profiles of Magnetic Massive Stars. https://arxiv.org/abs/1912.08748

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