Thermalization of long-lived nuclear isomeric states under stellar conditions

Abstract

view Abstract Citations (137) References (28) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Thermalization of long-lived nuclear isomeric states under stellar conditions Ward, R. A. ; Fowler, W. A. Abstract The paper examines the mechanisms by which the isomeric states of nuclei formed during nucleosynthesis are brought into statistical thermal equilibrium with their ground states. Simple two level and three-level systems are studied, followed by a more generalized technique for a numerical investigation of the internal thermal equilibrium of the ground and isomeric states in many key nuclei with emphasis on Al-26. In particular, regimes characterized by specified time scales and temperatures are studied in which (1) the ground state and the isomer may be considered a thermal mixture, or (2) the ground state and the isomer must be treated as separate nuclear species. The internal equilibrium time scales are calculated as a function of stellar temperature for given initial rates at which the isomer and the ground state are populated by their source reactions. Publication: The Astrophysical Journal Pub Date: May 1980 DOI: 10.1086/157983 Bibcode: 1980ApJ...238..266W Keywords: Isomerization; Nuclear Astrophysics; Nuclear Fusion; Stellar Structure; Thermalization (Energy Absorption); Aluminum 26; Chemical Equilibrium; Energy Levels; Magnesium Compounds; Nuclear Structure; Stellar Temperature; Astrophysics full text sources ADS |