Influence of isomeric states on astrophysical nucleosynthesis

Determine the influence of long-lived nuclear isomeric states on nucleosynthesis in astrophysical environments by incorporating isomeric states into reaction-network simulations and quantifying their impact on reaction rates and resulting elemental and isotopic abundances.

Background

The paper presents high-precision mass measurements of 76Cu that confirm a long-lived isomer with excitation energy Ex=64.8(25) keV and show that the previously observed 3− state is the isomer, not the ground state. This revision affects nuclear-structure interpretations and has implications for astrophysical reaction rates, including a 15% change in the photodissociation rate at T=2 GK due to a revised Q-value.

Motivated by these findings, the authors highlight that properly accounting for isomeric states in astrophysical environments may significantly affect nucleosynthesis pathways and final abundances. They note that the broader question of how isomeric states influence nucleosynthesis remains unresolved and emphasize the need to include isomers in network simulations.