Dr. Veronique Petit (FIT)

University of Florida Astronomy Colloquium - Jan. 28th, 2015

The Magnetism of Massive Stars

Low mass stars, like our sun, have long been known to display dynamo-generated magnetic activity. More massive stars, over five times the mass of our Sun, were not thought to be able to sustain such magnetic dynamos, despite observations that have indirectly suggested the possibility of magnetic fields at their surfaces. Until this decade, very few high-mass stars had been clearly identified as magnetic. The advent of a new generation of powerful spectropolarimeters has resulted in a flood of detailed information about the magnetic properties of massive stars. This presentation will describe new constraints on the nature and origins of magnetic fields in high-mass stars, provided by the Magnetism in Massive Stars project, and review our current understanding of the impact of magnetism on the lives of the most massive stars. I will also explain how it is possible to characterize the magnetic fields of stars thousands of light-years away by studying their polarized light. Finally, I will discuss how other observational diagnostics, e.g. optical and X-ray emission, relate to the inferred magnetic properties of these stars, and summarize prospects for future developments in our understanding of massive-star magnetospheres.