On the robustness of the r-process in neutron-star mergers against variations of nuclear masses

39th Symposium on Nuclear Physics 2016

Mendoza-Temis, J.J.^1,2 ; Wu, M.R.^3 ; Martínez-Pinedo, G.^3,4 ; Langanke, K.^3,4 ; Bauswein, A.^5,6 ; Janka, H.-T.^7 ; Frank, A.^1,2

Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, México, D.F.

04510, Mexico^1

Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México, México, D.F.

04510, Mexico^2

Institut für Kernphysik (Theoriezentrum), Technische Universität Darmstadt, Schlossgartenstraße 2, Darmstadt

64289, Germany^3

GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, Darmstadt

64291, Germany^4

Heidelberger Institut für Theoretische Studien, Schloss-Wolfsbrunnenweg 35, Heidelberg

69118, Germany^5

Department of Physics, Aristotle University of Thessaloniki, Thessaloniki

54124, Greece^6

Max-Planck-Institut für Astrophysik, Postfach 1317, Garching

85741, Germany^7

关键词: Neutron capture cross section;    Neutron number;    Neutron stars;    Neutron-induced fission;    Nuclei around;    Separation energy;    Smoothed particle hydrodynamics;    Statistical modeling;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/730/1/012018/pdf
DOI  :  10.1088/1742-6596/730/1/012018

来源: IOP

【 摘 要 】

r-process calculations have been performed for matter ejected dynamically in neutron star mergers (NSM), such calculations are based on a complete set of trajectories from a three-dimensional relativistic smoothed particle hydrodynamic (SPH) simulation. Our calculations consider an extended nuclear reaction network, including spontaneous, β- and neutron-induced fission and adopting fission yield distributions from the ABLA code. In this contribution we have studied the sensitivity of the r-process abundances to nuclear masses by using diferent mass models for the calculation of neutron capture cross sections via the statistical model. Most of the trajectories, corresponding to 90% of the ejected mass, follow a relatively slow expansion allowing for all neutrons to be captured. The resulting abundances are very similar to each other and reproduce the general features of the observed r-process abundance (the second and third peaks, the rare-earth peak and the lead peak) for all mass models as they are mainly determined by the fission yields. We find distinct differences in the predictions of the mass models at and just above the third peak, which can be traced back to different predictions of neutron separation energies for r-process nuclei around neutron number N = 130.