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The Connection between Binarity and Large-Scale Magnetic Fields in Hot, Massive Stars

Ordered magnetic fields are found in a variety of astrophysical objects, ranging from planets to Galaxies and beyond. While the details are not fully understood, magnetic fields in most objects are the result of dynamo processes that convert bulk mechanical motion into magnetic energy. Unlike lower mass stars like the Sun where magnetic fields are essentially ubiquitous, hot, massive stars (>1.5 solar masses) lack an important convective envelope and therefore are not expected to generate globally-ordered surface magnetic fields. Despite this fact, a rare fraction (~10%) of these stars host strong, stable, and globally-ordered magnetic fields with characteristics that contrast with the dynamo-generated fields of lower-mass stars, suggesting a very different origin. An attractive hypothesis that has been gaining momentum over the last few years is that these fields are the result of violent binary interactions. In this talk I will summarize the known properties of magnetic massive stars, review the growing evidence that could suggest binary interactions as the origin of the fields, and finally discuss the results of recent studies aimed at answering this open question.

Cody Hall

Jason Grunhut (Dunlap Institute)

October 28, 2016
14:00 - 15:00