Production of 26Al, 44Ti and 60Fe in Supernovae-sensitivity to the helium burning rates

TL;DR

This study investigates how uncertainties in helium burning reaction rates affect the predicted production of gamma-emitting isotopes in supernovae, highlighting significant sensitivities that impact astrophysical interpretations.

Contribution

It provides a detailed analysis of the sensitivity of supernova isotope yields to helium burning rate uncertainties and introduces a new rate for the 12C(alpha, gamma) reaction.

Findings

60Fe production varies by over a factor of five with rate uncertainties.

26Al and 44Ti yields vary by a factor of two to three.

Using different abundance standards significantly affects isotope yield predictions.

Abstract

We have studied the sensitivity of supernova production of the gamma emitting nuclei 26Al, 44Ti and 60Fe to variations of the rates of the triple alpha and 12C(alpha, gamma) reactions. Over a range of twice their experimental uncertainties we find variations in the production of 60Fe by more than a factor of five. Smaller variations, about a factor of two to three, were observed for 26Al and 44Ti. The yields of these isotopes change significantly when the abundances of Lodders (2003) are used instead of those of Anders and Grevesse (1989). These sensitivities will limit conclusions based on a comparison of observed gamma ray intensities and stellar models until the helium burning rates are better known. Prospects for improving the helium burning rates are discussed and a new version of the Boyes rate for 12C(alpha, gamma} is presented.