Nucleosynthesis inside Supernova-Driven Supercritical Accretion Disks

We have investigated 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 new-born compact object. It has been found that appreciable nuclear reactions take place even for a reasonable value of the viscosity parameter, αᵥᵢₛ 0.01, when the accretion rate ṁ = Ṁc²/(16 LEdd) > 10⁵, where LEdd is the Eddington luminosity. If ṁ ≥ 4 × 10⁶, all heavy elements are destroyed to 4 He through photodisintegrations at the inner part of the disk. Even 4 He is also disintegrated to protons and neutrons near the inner edge when ṁ ≥ 2 × 10⁷. If the fallback matter of the supernova explosion has the composition of a helium-rich layer of the progenitor, a considerable amount of 44 Ti could be ejected via a jet from the disk.