Nucleosynthesis inside Supernova-Driven Supercritical Accretion Disks

Abstract

Abstract We have investigated nucleosynthesis in a supercritical accretion disk around a compact object of $1.4\,{{{M}_{\odot}}}$, 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 new-born compact object. It has been found that appreciable nuclear reactions take place even for a reasonable value of the viscosity parameter, $\alpha_{\mathrm{vis}} \simeq 0.01$, when the accretion rate $\dot{m} = \dot{M}c^2/(16 L_{\mathrm{Edd}}) \gt 10^5$, where $L_{\mathrm{Edd}}$ is the Eddington luminosity. If $\dot{m} \ge 4 \times 10^6$, all heavy elements are destroyed to ${{4\atop} \mathrm{He}}$ through photodisintegrations at the inner part of the disk. Even ${{4\atop} \mathrm{He}}$ is also disintegrated to protons and neutrons near the inner edge when $\dot{m} \ge 2 \times 10^7$. If the fallback matter of the supernova explosion has the composition of a helium-rich layer of the progenitor, a considerable amount of ${{44\atop} \mathrm{Ti}}$ could be ejected via a jet from the disk.