The influence of fission on neutron star merger r-process and the position of the third r-process peak

M. Eichler, A. Arcones, A. Kelic, O. Korobkin, K. Langanke, G. Martinez-Pinedo, I. V. Panov, T. Rauscher, S. Rosswog, C. Winteler, N. T. Zinner, F. K. Thielemann

Research output: Chapter in Book/Report/Conference proceedingConference contribution


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 using four different fission fragment distribution models. Furthermore, we explore the origin of a shift in the third r-process peak position in comparison with the solar r-process abundances which has 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 β-decays compete and an (n,γ)-(γ,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 β-decay half-lives of nuclei with Z > 80, as suggested by recent theoretical advances, can partially prevent this shift.

Original languageEnglish
Title of host publicationProceedings of Science
PublisherProceedings of Science (PoS)
Publication statusPublished - 31 Dec 2014
Event13th Nuclei in the Cosmos, NIC 2014 - Debrecen, Hungary
Duration: 7 Jul 201411 Jul 2014


Conference13th Nuclei in the Cosmos, NIC 2014


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