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.
Bibliographical noteFunding Information:
Discussions with Roberto Gallino, Peter Möller, and Jerry Wasserburg are gratefully acknowledged. I thank the referee, Al Cameron, for many valuable criticisms. This work was supported in part by the Department of Energy under grants DE-FG02-87ER40328 and DE-FG02-00ER41149.
- Nuclear reactions, nucleosynthesis, abundances
- Stars: Population II
- Supernovae: general