Reference : Towards an Understanding of the Of?p star HD 191612: Optical Spectroscopy
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Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
Towards an Understanding of the Of?p star HD 191612: Optical Spectroscopy
Howarth, I. D. [Dept. Physics & Astronomy, University College London, Gower St., London WC1E 6BT, UK (]
Walborn, N. R. [> > > >]
Lennon, D. J. [> > > >]
Puls, J. [> > > >]
Nazé, Yaël mailto [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Sciences spatiales >]
Revista Mexicana de Astronomia y Astrofisica Conference Series
[en] HII regions ; ISM: jets and outflows ; stars: pre-main sequence ; stars: mass loss
[en] We have acquired extensive optical spectroscopy of the early-type magnetic star HD 191612 (O6.5f?pe-O8fp). The Balmer and HeI lines show strongly variable emission which is extremely reproducible on a well-determined 538-d period. Metal lines and HeII absorptions (including many selective emission lines, but excluding HeII lambda 4686 Å emission) are nearly constant in line strength, but are variable in velocity. The radial-velocity variations establish a double-lined binary orbit with P_{orb} = 1542d, e = 0.44; by elimination, rotational modulation of a magnetically constrained plasma is left as by far the most likely `clock' underlying the 538-d changes. The implied rotation period shows that slow rotators can easily be hidden in the O-star population, with gaussian-like `turbulence' dominating the line widths.

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