[Triumf-seminars] TRIUMF Colloquium today at 14:00

[postmaster at admin.triumf.ca]

Date/Time: Tue 2010-02-16 at 14:00

Location:  Auditorium          

Speaker:   Almudena Arcones (TU Darmstadt/GSI)

Title:     Explosive nucleosynthesis in core-collapse supernovae

Abstract: The specific mechanism and astrophysical site for the production of half of the heavy elements, the so-called r-nuclei, remains to be found. We address this problem making improvements along two main fronts: the astrophysical environment and the properties of nuclei far from stability. Observational data indicate that there are two components. The heavy r-process nuclei (A>130) are produced by rapid neutron capture in a yet unknown site. The other component corresponds to the "lighter heavy nuclei" or weak r-process. These nuclei are produced by charge-particle reactions (CPR) and neutron captures in what it was also known as light element primary process (LEPP). Our nucleosynthesis studies are based on trajectories of hydrodynamical simulations for core-collapse supernovae and their subsequent neutrino-driven winds. We show that LEPP elements can be produced in neutrino-driven winds and we relate their abundances to the neutrino emission from the nascent neutron star. Based on the latest hydrodynamical simulations, heavy r-process elements cannot be synthesized in the neutrino-driven winds. However, by artificially increasing the wind entropy, elements up to A=195 can be made. In this way one can mimic the general behavior of ejecta where the r-process occurs. We use this approach to study the impact of the nuclear physics input (nuclear masses, neutron capture cross sections, and beta-delayed neutron emission) and of the long-time dynamical evolution on the final abundances.

Stimulants will be available 15 minutes before the talk.

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