Sensitivity to neutron captures and beta-decays of the enhanced s-process in rotating massive stars at low metallicities

TL;DR

This paper investigates how nuclear physics uncertainties affect the enhanced s-process in rotating massive stars at low metallicities, revealing significant uncertainties in isotope abundances mainly due to neutron capture rate variations.

Contribution

It introduces a Monte-Carlo framework to quantify nuclear physics uncertainties in the enhanced s-process at low metallicity, highlighting the impact of reaction rate uncertainties.

Findings

Abundance uncertainties exceed a factor of 2 for several isotopes.

Neutron capture rate uncertainties are the primary source of abundance variation.

Beta-decay uncertainties affect a few nuclei near branching points.

Abstract

The s-process in massive stars, producing nuclei up to $A\approx 90$, has a different behaviour at low metallicity if stellar rotation is significant. This enhanced s-process is distinct from the s-process in massive stars around solar metallicity, and details of the nucleosynthesis are poorly known. We investigated nuclear physics uncertainties in the enhanced s-process in metal-poor stars within a Monte-Carlo framework. We applied temperature-dependent uncertainties of reaction rates, distinguishing contributions from the ground state and from excited states. We found that the final abundance of several isotopes shows uncertainties larger than a factor of 2, mostly due to the neutron capture uncertainties. A few nuclei around branching points are affected by uncertainties in the $\beta$-decay.