Astromers: Nuclear Isomers in Astrophysics
- 17 December 2020
- journal article
- research article
- Published by American Astronomical Society in The Astrophysical Journal Supplement Series
- Vol. 252 (1), 2
- https://doi.org/10.3847/1538-4365/abc41d
Abstract
We develop a method to compute thermally mediated transition rates between the ground state and long-lived isomers in nuclei. We also establish criteria delimiting a thermalization temperature above which a nucleus may be considered a single species and below which it must be treated as two separate species: a ground-state species and an astrophysical isomer ("astromer") species. Below the thermalization temperature, the destruction rates dominate the internal transition rates between the ground state and the isomer. If the destruction rates also differ greatly from one another, the nuclear levels fall out of or fail to reach thermal equilibrium. Without thermal equilibrium, there may not be a safe assumption about the distribution of occupation probability among the nuclear levels when computing nuclear reaction rates. In these conditions, the isomer has astrophysical consequences and should be treated as a separate astromer species which evolves separately from the ground state in a nucleosynthesis network. We apply our transition-rate methods and perform sensitivity studies on a few well-known astromers. We also study transitions in several other isomers of likely astrophysical interest.Keywords
This publication has 21 references indexed in Scilit:
- Stellar origin of the 182 Hf cosmochronometer and the presolar history of solar system matterScience, 2014
- The Shell-Model Code NuShellX@MSUNuclear Data Sheets, 2014
- Nuclear Data Sheets forNuclear Data Sheets, 2014
- Nuclear Data Sheets for A = 34Nuclear Data Sheets, 2012
- THE EFFECTS OF THERMONUCLEAR REACTION RATE VARIATIONS ON 26 Al PRODUCTION IN MASSIVE STARS: A SENSITIVITY STUDYThe Astrophysical Journal Supplement Series, 2011
- Nuclear Data Sheets for A = 113Nuclear Data Sheets, 2010
- Nuclear Data Sheets for A = 81Nuclear Data Sheets, 2008
- New “USD” Hamiltonians for theshellPhysical Review C, 2006
- RATE TABLES FOR THE WEAK PROCESSES OF pf-SHELL NUCLEI IN STELLAR ENVIRONMENTSAtomic Data and Nuclear Data Tables, 2001
- Lifetimes ofandin an astrophysical plasmaPhysical Review C, 1999