Nucleosynthesis in Neutron Star Mergers and Core-Collapse Supernovae

Thursday 8 June 2017, 2.00PM to 3.00pm

Speaker(s): Dr Marius Eichler, TU Darmstadt, Germany

As of today, binary neutron star mergers are the most promising scenario for the astrophysical r-process site. Very neutron-rich conditions in the dynamic ejecta lead to fission cycling and guarantee that the resulting nuclear composition is largely independent from the hydrodynamical evolution. Recent nucleosynthesis calculations of the r-process in dynamic ejecta lead to a shift in the third r-process peak compared to the solar abundance pattern. I will show how the shift depends on the conditions at the time of freeze-out from (n,γ)-(γ,n) equilibrium and discuss the impact of nuclear mass models, fission fragment distribution models, and β-decay rates on the r-process peaks. Furthermore, I will address the nucleosynthesis of the p-nuclei 92,94Mo and 96,98Ru in 2D core-collapse supernova simulations of a 11.2 M⊙ and a 17.0 M⊙ star. While we observe the production of 92Mo and 94Mo in slightly neutron-rich as well as proton-rich regions, 96,98Ru can only be produced efficiently via the νp-process. This disentanglement of production mechanisms has interesting consequences when comparing to the abundance ratios between these isotopes in the solar system and in presolar grains.

Location: G/002