Sensitivity studies for a weak $r$ process: neutron capture rates

R. Surman, M. Mumpower, R. Sinclair, K. Jones, W. Hix, G. C. McLaughlin

AIP Advances 4, 041008 (2014)

Rapid neutron capture nucleosynthesis involves thousands of nuclear species far from stability, whose nuclear properties need to be understood in order to accurately predict nucleosynthetic outcomes. Recently sensitivity studies have provided a deeper understanding into how the $r$ process proceeds and have identified pieces of nuclear data of interest recommended for further experimental or theoretical study. A key result of these studies has been to point out the importance of individual neutron capture rates in setting the final $r$-process abundance pattern for a 'main' ($A\sim 130$ peak and above) $r$ process. Here we examine neutron capture in the context of a 'weak' $r$ process that forms primarily the $A\sim 80$ $r$-process abundance peak. We identify the astrophysical conditions required to produce this peak region through weak $r$-processing and point out the neutron capture rates that most strongly influence the final abundance pattern.