On nucleosynthesis in supernovae beyond the iron peak

An rbc-process (rapid with back coupling) is proposed for synthesizing nuclei beyond the iron peak at the high temperatures, densities, and neutron excess found in superova explosions. The detailed balancing of (p, gamma) and (gamma, p) reactions will break down for high-Z elements, causing all nuclei to fall into either of two groups. The main group of nuclei will have relative abundances conforming to the equations of nuclear statistical equilibrium, but the heavier nuclei will come into kinetic equilibrium through (gamma, p) reactions and beta(-) processes. Calculations for the group of nuclei having A values between 75 and 120 agree qualitatively with the general trend of the observed abundance curve.