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Arts & Sciences
[PAST EVENT] PHYSICS SEMINAR
February 5, 2015
3:30pm
Abstract
We discuss a neutrino-driven neutron capture mechanism that occurs in the He shell of an early core-collapse supernova. We calculate the nucleosynthesis both before and after the passage of shock, in recent pre-supernova models of 11-15 M?. We find that inverted neutrino mass hierarchy can lead to neutron capture on a timescale of ~100-300 s which is much slower than the conventional rapid neutron capture process. This process is uniquely sensitive to the neutron capture cross-sections which affect both the timescale and the final abundance. We explore the sensitivity of the mechanism on the neutrino emission parameters and oscillations, as well as the effect of explosion energy and progenitor metallicity. We find that abundance pattern observed in the so called Carbon Enhanced Metal-Poor r+s stars which is still a puzzle, can be explained very well by our mechanism.
We discuss a neutrino-driven neutron capture mechanism that occurs in the He shell of an early core-collapse supernova. We calculate the nucleosynthesis both before and after the passage of shock, in recent pre-supernova models of 11-15 M?. We find that inverted neutrino mass hierarchy can lead to neutron capture on a timescale of ~100-300 s which is much slower than the conventional rapid neutron capture process. This process is uniquely sensitive to the neutron capture cross-sections which affect both the timescale and the final abundance. We explore the sensitivity of the mechanism on the neutrino emission parameters and oscillations, as well as the effect of explosion energy and progenitor metallicity. We find that abundance pattern observed in the so called Carbon Enhanced Metal-Poor r+s stars which is still a puzzle, can be explained very well by our mechanism.