Revealing stellar and explosive nucleosynthesis with COSI

The Compton Spectrometer and Imager (COSI) is a 0.2-5 MeV Compton telescope capable of performing high resolution spectroscopy and imaging of astrophysical sources. In particular, the excellent energy resolution of COSI’s germanium semiconductor detectors uniquely equips it to study the MeV gamma-ray line signatures of stellar and explosive nucleosynthesis across the Milky Way Galaxy and beyond. As a NASA Small Explorer satellite mission slated for launch in 2027, COSI will shed light on the origin, dynamics, and distribution of radioactive isotopes including Al-26, Fe-60, and Ti-44. It can also probe nucleosynthetic signatures of multi-messenger events including neutron star mergers and nearby supernovae. This presentation will detail COSI’s expected contributions to the spectroscopy and imaging of these sites of nucleosynthesis in the upcoming era of improved MeV sensitivity.