19 November 2009

Speaker: Nathan Smith (UC Berkeley)

Title:Eta Carinae and Pre-Supernova Temper Tantrums of Massive Stars

Abstract:The evolved massive stars known as luminous blue variables (LBVs) have enjoyed renewed interest in recent years for three reasons: 1) we have learned that eruptions of LBVs probably dominate the total mass lost during a star's lifetime, strongly influencing the star's death, 2) their eruptions make up many of the transient sources fainter than supernovae that will be discovered in increasing numbers in coming years, and 3) LBVs are the likely progenitors of the most luminous supernovae known, giving us a potential window to the deaths of massive stars in the early universe. Despite astonishing mass-loss rates of as much as 1 Msun/yr and total energies of more than 1e50 ergs, the physical mechanism driving these recurring eruptions remains unexplained after decades of research. There is hope that the new wave of transients will help improve the situation. With that in mind, I will begin by summarizing what we have learned from detailed study of Eta Carinae, the poster-child for giant eruptions of unstable massive stars. I will then discuss how this well-studied example fits in with the range of observed LBV properties, what some outstanding mysteries are, and how this can help guide our intuition for studying luminous supernovae and eruptive transients that result from similar stars in other galaxies. For those who are not particularly interested in massive stars, I may show amusing pictures of recent Harvard graduates who are now postdocs at Berkeley.

Video of the Presentation (Talks can be viewed with RealPlayer. Free download is available from www.real.com )