Successful nu-p process in neutrino-driven outflows in core-collapse supernovae

An enduring mystery in nuclear astrophysics pertains to the relatively high observed abundances of the proton-rich isotopes 92,94-Mo and 96,98-Ru. An attractive proposal to solve this problem is called the nu p-process. This process could operate in a core-collapse supernova (CCSN) hot bubble, which is formed by a neutrino-driven outflow from the surface of the protoneutron star (PNS) after the shock is launched. However, years of detailed studies have cast doubt over its viablity to generate the observed abundances of these nuclides. These difficulties became more dire with recent calculations that took into account in-medium effects enhancing the rate of the triple-alpha reaction.

Here, we revisit the problem and present an example calculation, using a self-consistent, spherically symmetric neutrino-driven outflow model, in which both the required absolute yields of the Mo and Ru p-nuclides and the observed isotopic ratios are successfully reproduced, even with an enhanced triple-alpha rate.