Taking into account the increasing mass of a central object through fall-back, we investigated nucleosynthesis inside an accretion disk formed during a core collapse of a massive star. It has been confirmed that the disk is an advection-dominated accretion flow supported by gas or radiation pressure. A sequence of (α, γ) reactions take place and Fe-group elements are produced inside the disk. At the early phase of the fall-back, when O-rich materials inflow, the ejected gas contains abundant 54Fe and 56,58Ni. At the late phase the in-coming material is He-rich and the out-going gas is abundant of 44Ti as well as Fe and Ni. Provided that the processed gas outflows from the inner region up to the ejection radius, rej, we find that the ejected mass of the heavy elements is not very sensitive to rej, as long as we take rej ≥ 50r g, because these elements are produced mainly in the region 20-100rg.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science