Nucleosynthesis inside an Accretion Disk in a Collapsar

We investigate nucleosynthesis inside an accretion disk formed during a collapse of a massive star. The mass accretion rate and the mass of a central object vary with time according to a fall-back scenario. The disk is confirmed to be dominated by advection. A considerable amount of Fe-group elements is produced inside the disk through a sequence of (α, γ) reactions, and the processed material is ejected via outflows. The collapsar accretion disk is an promising site for production of heavy elements.