Production of 44Ti and Iron-group Nuclei in the Ejecta of 3D Neutrino-driven Supernovae

Abstract

The radioactive isotopes ^44 Ti and ^56 Ni are important products of explosive nucleosynthesis, which play a key role in supernova (SN) diagnostics and have been detected in several nearby young SN remnants. However, most SN models based on nonrotating single stars predict yields of ^44 Ti that are much lower than the values inferred from observations. We present, for the first time, the nucleosynthesis yields from a self-consistent three-dimensional SN simulation of a ∼19 M _⊙ progenitor star that reaches an explosion energy comparable to that of SN 1987A and that covers the evolution of the neutrino-driven explosion until more than 7 s after core bounce. We find a significant enhancement of the Ti/Fe yield compared to recent spherically symmetric (1D) models and demonstrate that the long-time evolution is crucial to understanding the efficient production of ^44 Ti due to the nonmonotonic temperature and density history of the ejected material. Additionally, we identify characteristic signatures of the nucleosynthesis in proton-rich ejecta, in particular high yields of ^45 Sc and ^64 Zn.

Keywords

• Core-collapse supernovae
• Supernova remnants
• Gamma-ray sources
• Explosive nucleosynthesis
• Nucleosynthesis