The role of fission in the r-process

Abstract

We have developed a full set of fission rates that include spontaneous fission, neutron-induced fission, beta-delayed fission and, neutrino-induced fission, that are supplemented with realistic distributions of fission yields. Using this new input data we have carried out r-process calculations assuming adiabatic expansions that mimic the conditions achieved in the supernova neutrino driven wind. We have explored the sensitivity of the final abundances to different mass models. The resulting abundance distribution turns out to be very sensitive to the strength of the N = 82 shell gap far from stability. Mass models with a strong shell gap converge to an r-process distribution that is independent of the initial conditions once fission sets in. This convergence is not achieved in mass models with a quenched N = 82 shell gap. (c) 2007 Published by Elsevier B.V.