## Astromers in the radioactive decay of r-process nuclei

### G. W. Misch, T. M. Sprouse, M. Mumpower

Published ApJL 913 L2 (2021)

We study the impact of astrophysically relevant nuclear isomers (astromers) in the context of the rapid neutron capture process (r-process) nucleosynthesis. We compute thermally mediated transition rates between long-lived isomers and the corresponding ground states in neutron-rich nuclei. We calculate the temperature-dependent beta-decay feeding factors which represent the fraction of material going to each of the isomer and ground state daughter species from the beta-decay parent species. We simulate nucleosynthesis by including as separate species nuclear excited states with measured terrestrial half-lives greater than 100 microseconds. We find a variety of isomers throughout the chart of nuclides are populated, and we identify those most likely to be influential. We comment on the capacity of isomer production to alter radioactive heating in an r-process environment.

LA-UR-20-29246

## Mail

Matthew Mumpower
Los Alamos National Lab
MS B283
TA-3 Bldg 123
Los Alamos, NM 87545