R-Process Nucleosynthesis in Core-Collapse Supernova Explosions and Binary Neutron Star Mergers

Abstract

Beta decay rates for exotic nuclei with neutron magic number of \\(N=126\\) relevant to r-process nucleosynthesis are studied up to \\(Z=78\\) by shell model calculations. The half-lives for the waiting-point nuclei, which are found to be short compared to a standard finite-range-droplet model (FRDM), are used to study r-process nucleosynthesis in core-collapse supernova explosions and binary neutron star mergers. The element abundances are obtained up to third peak as well as beyond the peak region up to thorium and uranium. We find that thorium and uranium elements are produced more with the shorter shell-model half-lives and their abundances come close to the observed values in core-collapse supernova explosions. In case of binary neutron star mergers, thorium and uranium are produced as much as consistent with the observed values independent of the half-lives.