An r-process scenario with fission but without fission cycling is considered to account for the observed abundance patterns of neutron-capture elements in ultra-metal-poor stars. It is proposed that neutrino reactions play a crucial role in inducing the fission of the progenitor nuclei after the r-process freezes out in type II supernovae. To facilitate neutrino-induced fission, the proposed r-process scenario is restricted to occur in a low-density environment, such as the neutrino-driven wind from the neutron star. Further studies to develop this scenario are emphasized.
- Nuclear reactions, nucleosynthesis, abundances
- Stars: Population II
- Supernovae: general