Supernova explosions of very massive stars as a rare r process site
Tobias Fischer1, Meng-Ru Wu2,3*, Benjamin Wehmeyer4,5, Gabriel Martinez-Pinedo6,7, Niels-Uwe F. Bastian1, David B. Blaschke1,8,9
1Institute for Theoretical Physics, University of Wroclaw, Wroclaw, Poland
2Institute of Physics, Academia Sinica, Taipei, Taiwan
3Institute of Astronomy and Astrophysics, Academia Sinica, Taipei, Taiwan
4Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Budapest, Hungary
5Centre for Astrophysics Research, University of Hertfordshire, Hatfield, UK
6GSI Helmholtz Center for Heavy Ion Research, Darmstadt, Germany
7Institute for Nuclear Physics, TU Darmstadt, Darmstadt, Germany
8Bogoliubov Laboratory for Theoretical Physics, Joint Institute for Nuclear Research, Dubna, Russian Federation
9National Research Nuclear University, Moscow, Russian Federation
* Presenter:Meng-Ru Wu,
Supernova explosions of massive stars are one of the primary sites for the production of the elements in the universe. The common picture assumes that most stars with zero-age main sequence masses in the range of 40-50 solar masses belong to the failed supernova explosion branch. Contrarily, it has been demonstrated recently that the appearance of exotic phases of hot and dense matter, associated with a first-order phase transition from nuclear matter to the quark matter at high densities, can trigger supernova explosions these massive stars. Here, we present result s obtained from the nucleosynthesis analysis for material ejected from the surface of the newly born proto-neutron star of such supernova explosions. We find that the ejecta contain an early low entropy neutron-rich component and a late-time high-entropy neutrino-driven wind. The latter enables not only the nucleosynthesis to robustly overcome the second r-process peak at nuclear mass number A~130, but also proceeds beyond the formation of the third peak (A~195) to the actinides. These yields can account for metal-poor star observations concerning the r-process elements such as strontium and europium in the galaxy at low metalicity. The actinide yields also suggests that this source may be a candidate contributing to the abundances of radioactive 244Pu measured in the Earth sediments.

Keywords: supernovae, r-process nucleosynthesis