2021/03/17 by G. Wendell Misch, Misch, G. Wendell, T. M. Sprouse +11
Engineering · Physics and Astronomy · #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #Nuclear Physics and Applications #Nuclear Theory (nucl-th) #Nuclear physics research studies #Nuclear reactor physics and engineering
paper · pdf · doi:10.48550/arxiv.2103.09392
openalex publication_date 2021/03/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Nuclear isomers are populated in the rapid neutron capture process (r process) of nucleosynthesis. The r process may cover a wide range of temperatures, potentially starting from several tens of GK (several MeV) and then cooling as material is ejected from the event. As the r-process environment cools, isomers can freeze out of thermal equilibrium or be directly populated as astrophysical isomers (astromers). Two key behaviors of astromers -- ground stateisomer transition rates and thermalization temperatures -- are determined by direct transition rates between pairs of nuclear states. We perform a sensitivity study to constrain the effects of unknown transitions on astromer behavior. We also introduce a categorization of astromers that describes their potential effects in hot environments. We provide a table of neutron-rich isomers that includes the astromer type, thermalization temperature, and key unmeasured transition rates.