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Past Events
An Intermediate-Mass Binary Star Origin of Long Gamma-ray Bursts
| Speaker: | Dr. Herbert Lau |
| Affiliation: | Centre for Stellar and Planetary Astrophysics, Monash University, Australia |
| Date: | December 21, 2009 (Mon) |
| Time: | 11:00a.m. - 12:00 n.n. |
| Venue: | Room 522, 5/F, Chong Yuet Ming Physics Building, HKU |
Abstract:
The stellar origin of gamma-ray bursts can be explained by the rapid release of energy in a highly collimated, extremely relativistic jet. This in turn appears to require a rapidly spinning highly magnetised stellar core that collapses into a magnetic neutron star or a black hole within a relatively massive envelope. To satisfy all these requirements we hypothesize a binary star model that ends with the merging of an oxygen neon white dwarf with the carbon/oxygen core of a naked helium star at the end of a common envelope phase of evolution. The rapid spin and high magnetic field are a natural consequence of such a merging. The evolution that leads to these progenitors is convoluted and so naturally occurs only very rarely. To test the hypothesis we evolve a population of progenitors and find that the rate is as required.
Coffee and tea will be served 20 minutes prior to the seminar.