Nuclear Gamma Rays and Cosmic Nucleosynthesis

Cosmic nucleosynthesis is encoded in the variety of isotopes we can observe in today’s universe. Deciphering how this cumulative result may build up from the characteristics of nuclear fusion rates in sites of nucleosynthesis such as stars and stellar explosions however remains a challenge, as these extreme environments imply occultation for direct measurements and rare opportunities due to rapid dynamics. But new astronomies have been found to complement abundance data from our solar system and the mixture of stars, and these can address specific aspects of the cosmic cycle of matter. Space-based gamma-ray telescopes have observed nuclear emission from freshly-produced and unstable isotopes as they decay in interstellar space. In this talk we will discuss what has been learned from more than two decades of nuclear gamma ray spectroscopy on the interiors of stars and supernovae and how they spread new nuclei in interstellar space. We will also address how this, together with a new variety of messengers from nucleosynthesis, has led us beyond the concept of universal processes that were the corner stones when broader nuclear astrophysics research started more than 60 years ago.