A MiMeS analysis of the magnetic field and circumstellar environment of the weak-wind O9 sub-giant star HD 57682

I will review our recent analysis of the magnetic properties of the O9IV star HD 57682, using spectropolarimetric observations obtained with ESPaDOnS at the Canada-France-Hawaii telescope within the context of the Magnetism in Massive Stars (MiMeS) Large Program. I discuss our most recent determination of the rotational period from longitudinal magnetic field measurements and Halpha variability - the latter obtained from over a decade's worth of professional and amateur spectroscopic observations. Lastly, I will report on our investigation of the magnetic field geometry and the effects of the field on the circumstellar environment.Comment: 2 pages, 2 figures, IAUS272 - Active OB Stars: Structure, Evolution, Mass Loss and Critical Limit

Of?p stars: a class of slowly rotating magnetic massive stars

Only 5 Of?p stars have been identified in the Galaxy. Of these, 3 have been studied in detail, and within the past 5 years magnetic fields have been detected in each of them. The observed magnetic and spectral characteristics are indicative of organised magnetic fields, likely of fossil origin, confining their supersonic stellar winds into dense, structured magnetospheres. The systematic detection of magnetic fields in these stars strongly suggests that the Of?p stars represent a general class of magnetic O-type stars.Comment: Proceedings of IAUS 272: Active OB star