The Impact of Nuclear Physics during Stellar Core Collapse

Abstract

Nuclear electron capture and the nuclear equation of state play important roles during the collapse of a massive star and the subsequent supernova. The nuclear equation of state controls the nature of the bounce which initially forms the supernova shock while electron capture determines the location where the shock forms. Advances in nuclear structure theory have allowed a more realistic treatment of electron capture on heavy nuclei to be developed. We will review how this improvement has led to a change in our understanding of stellar core collapse, with electron capture on nuclei with masses larger than 50 found to dominate electron capture on free protons, resulting is significant changes in the hydrodynamics of core collapse and bounce. We will also demonstrate the impact of a variety of nuclear equations of state on supernova shock propagation. Of particular note is the interplay between the nuclear composition determined by the equation of state and nuclear electron capture. 10th Symposium on Nuclei in the Cosmos

Evaluating nuclear physics inputs in core-collapse supernova models

“…The differences in shock progression (Fig. 2, upper) are comparable to, but smaller than, those seen by [20,19,21], who used the LMSH EC as we did, but larger than the differences seen by [22] who did not and therefore Y e reduction during collapse was dominated by capture on free nucleons, the abundances of which are affected by E sym . Each of the referred simulations used a different 15 M progenitor and a different opacity set which complicates the comparison.…”

“…The differences at bounce between the models using the LS and STOS EoSs originate primarily in the NSE region during collapse where the STOS EoS gives a lower abundance of heavy nuclei, resulting in less EC by nuclei [19] and therefore a larger initial shock position (0.49 M versus 0.44 M for the LS 180 EoS model, Fig. 2 lower).…”