Reaction Rate Sensitivity of the Production of γ-Ray Emitting Isotopes in Core-collapse Supernovae

Abstract

Abstract Radioactive isotopes produced in core-collapse supernovae (CCSNe) provide useful insights into the underlying processes driving the collapse mechanism and the origins of elemental abundances. Their study generates a confluence of major physics research, including experimental measurements of nuclear reaction rates, astrophysical modeling, and γ-ray observations. Here we identify the key nuclear reaction rates to the nucleosynthesis of observable radioactive isotopes in explosive silicon burning during CCSNe. Using the nuclear reaction network calculator SkyNet and current REACLIB reaction rates, we evolve temperature–density–time profiles of the innermost 0.45 M ⊙ ejecta from the core collapse and explosion of a 12 M ⊙ star. Individually varying 3403 reaction rates by factors of 100, we identify 141 reactions that cause significant differences in the isotopes of interest, namely, 43K, 47Ca, 44,47Sc, 44Ti, 48,51Cr, 48,49V, 52,53Mn, 55,59Fe, 56,57Co, and 56,57,59Ni. For each of these reactions, we present a novel method to extract the temperature range pertinent to the nucleosynthesis of the relevant isotope; the resulting temperatures lie within the range T = 0.47–6.15 GK. Limiting the variations to within 1σ of STARLIB reaction rate uncertainties further reduces the identified reactions to 48 key rates, which can be used to guide future experimental research. Complete results are presented in tabular form.