Treatment of isomers in nucleosynthesis codes

TL;DR

This paper introduces a comprehensive method for explicitly treating nuclear isomers in stellar nucleosynthesis simulations, accounting for their thermal population and decay properties, which are crucial for accurate modeling of isotope destruction in stars.

Contribution

It provides a general approach and an online code for incorporating isomers into nucleosynthesis calculations, addressing a key challenge in astrophysical modeling.

Findings

The approach accounts for thermal excitation and de-excitation of isomers.

Explicit treatment improves the accuracy of isotope destruction predictions.

The code is publicly available for use in stellar nucleosynthesis models.

Abstract

The decay properties of long-lived excited states (isomers) can have a significant impact on the destruction channels of isotopes under stellar conditions. In sufficiently hot environments, the population of isomers can be altered via thermal excitation or de-excitation. If the corresponding lifetimes are of the same order of magnitude as the typical time scales of the environment, the isomers have to be the treated explicitly. We present a general approach to the treatment of isomers in stellar nucleosynthesis codes and discuss a few illustrative examples. The corresponding code is available online at http://exp-astro.de/isomers/