Insights into the Production of ⁴⁴Ti and Nickel Isotopes in Core-collapse Supernovae

We report nucleosynthetic results for both ⁴⁴Ti and nickel isotopes for 18 three-dimensional (3D) core-collapse supernova (CCSN) simulations extended to ∼20 s after bounce. We find that many of our long-term models are able to achieve ⁴⁴Ti/⁵⁶Ni ratios similar to that observed in Cassiopeia A, and modern supernova models can synthesize up to 2 × 10⁻⁴ M _⊙ of ⁴⁴Ti. Neutrino-driven winds and the fact that there can be simultaneous accretion and explosion in 3D models of CCSNe play central roles in its production. We conclude that the ⁴⁴Ti underproduction problem in previous CCSN models is no longer an issue. In addition, we discuss the production of both ⁵⁷Ni and stable nickel/iron ratios and compare our results to observations of SN 1987A and the Crab.