Nucleosynthesis inside Supernova-Driven Supercritical Accretion Disks

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.