p‐Process Nucleosynthesis inside Supernova‐driven Supercritical Accretion Disks

We investigate p -process nucleosynthesis in a supercritical accretion disk around a compact object of 1.4 M ☉ , using the self-similar solution of an optically thick advection-dominated flow. Supercritical accretion is expected to occur in a supernova with fallback material accreting onto a newborn compact object. It is found that an appreciable number of p -nuclei are synthesized via the p -process in supernova-driven supercritical accretion disks (SSADs) when the accretion rate = c 2 /(16 L Edd ) > 10 5 , where L Edd is the Eddington luminosity. Abundance profiles of p -nuclei ejected from SSADs have features similar to those of the oxygen/neon layers in Type II supernovae when the abundance of the fallback gas far from the compact object is that of the oxygen/neon layers in the progenitor. The overall abundance profile is in agreement with that of the solar system. Some p -nuclei, such as Mo, Ru, Sn, and La, are underproduced in the SSADs as in Type II supernovae. If the fallback gas is mixed with a small fraction of protons through Rayleigh-Taylor instability during the explosion, significant amounts of 92 Mo are produced inside the SSADs. Isotopes 96 Ru and 138 La are also produced when the fallback gas contains abundant protons, although the overall abundance profile of p -nuclei is rather different from that of the solar system. The p -process nucleosynthesis in SSADs contributes to the chemical evolution of p -nuclei, in particular 92 Mo, if several percent of the fallback matter are ejected via jets and/or winds.