Experimentally Constraining the Nucleosynthesis of ⁶⁰Fe in Massive Stars

The stellar nucleosynthesis of ⁶⁰Fe is currently a topic of great interest to the nuclear astrophysics community. Observations of the decay signature of the long-lived radioisotopes ⁶⁰Fe and ²⁶Al by γ-ray observatories have offered a unique observational constraint on massive star models. As both isotopes are thought to be co-produced in massive stars, the observed ratio of the line intensities is expected to be well predicted by the models. Meaningful comparisons between models and observation depend crucially on reliable inputs concerning the underlying nuclear reactions, and while much work has been performed by stellar modelers to resolve an initial disagreement with observation, the production and destruction cross sections for ⁶⁰Fe nucleosynthesis have remained purely theoretical. The purpose of this work is to experimentally constrain the primary production and destruction reactions, ⁵⁹Fe(n,γ)⁶⁰Fe and ⁶⁰Fe(n,γ)⁶¹Fe respectively, through Coulomb dissociation and direct neutron activation techniques.