Darmstadt 2016 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 50: Nuclear Astrophysics IV

HK 50.1: Gruppenbericht

Donnerstag, 17. März 2016, 14:00–14:30, S1/01 A04

The role of nuclear inputs in r-process nucleosynthesis — •Samuel Andrea Giuliani, Alexander Arzhanov, Stephen Frieß, Gabriel Martínez-Pinedo, Heiko Möller, Andre Sieverding, and Meng-Ru Wu — TU Darmstadt

We have studied the sensitivity of the r-process abundances produced in dynamical ejecta from neutron star mergers to different nuclear mass models. For each mass model, the resulting abundances are almost independent of the astrophysical conditions and reproduce the general features of the observed r-process abundance. We find that the second peak around A∼ 130 is produced by the fission yields of the material that piles up in nuclei with A≳ 250. We also find distinct differences in the predictions at and just above the third peak (A ∼ 195) for different mass models, due to different neutron separation energies at N=130.

Due to the crucial role that fission plays in r-process nucleosynthesis, we have computed the fission properties of superheavy nuclei using the BCPM energy density functional. We found that certain combinations of neutron and proton number lead to an enhanced stability against the spontaneous fission process, related with the existence of magic numbers in the superheavy region. However, the systematic of the fission properties is strongly affected by the choice of the collective degree of freedom when the fission path is obtained by minimizing the action integral. Finally, a comparison with other theoretical models and the consequences for r-process nucleosynthesis are discussed.

This work was supported by the Helmholtz Association through the Nuclear Astrophysics Virtual Institute (VH-VI-417).