http://arxiv.org/abs/1411.0974
The comparison between observational abundance features and those obtained from nucleosynthesis predictions of stellar evolution and/or explosion simulations can scrutinize two aspects: (a) the conditions in the astrophysical production site and (b) the quality of the nuclear physics input utilized. Here we test the abundance features of r-process nucleosynthesis calculations for the dynamical ejecta of neutron star merger simulations based on three different nuclear mass models: The Finite Range Droplet Model (FRDM), the (quenched version of the) Extended Thomas Fermi Model with Strutinsky Integral (ETFSI-Q), and the Hartee-Fock-Bogoliubov (HFB) mass model. We make use of corresponding fission barrier heights and compare the impact of four different fission fragment distribution models on the final r-process abundance distribution. Furthermore, we explore the origin of a shift in the third r-process peak position in comparison with the solar r-process abundances which have been noticed in a number of merger nucleosynthesis predictions. We show that this shift occurs during the r-process freeze-out when neutron captures and beta-decays compete and an (n,g)-(g,n) equilibrium is not maintained anymore. During this phase neutrons originate mainly from fission of material above A = 240. We also demonstrate that a faster (and thus earlier) release of these neutrons, e.g., by shorter beta-decay half-lives of nuclei with Z > 80, as suggested by recent theoretical advances, can partially prevent this shift.
M. Eichler, A. Arcones, A. Kelic, et. al.
Wed, 5 Nov 14
25/61
Comments: N/A
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