Production of 26Al, 44Ti, and60Fe in core-collapse supernovae: Sensitivity to the rates of the triple alpha and12C(α,γ)16O reactions

Abstract

We have studied the sensitivity to variations in the triple alpha and 12C(α, γ)16O reaction rates of the production of 26Al, 44Ti, and 60Fe in core-collapse supernovae (SNe). We used the KEPLER code to model the evolution of 15 M⊙, 20 M⊙, and 25 M⊙ stars to the onset of core collapse and simulated the ensuing SN explosion using a piston model for the explosion and an explosion energy of 1.2 × 1051 erg. Calculations were performed for the Anders & Grevesse and Lodders abundances. Over a range of twice the experimental uncertainty, σ, for each helium-burning rate, the production of 26Al, 60Fe, and their ratio vary by factors of 5 or more. For some species, similar variations were observed for much smaller rate changes, 0.5σ or less. The production of 44Ti was less sensitive to changes in the helium-burning rates. Production of all three isotopes depended on the solar abundance set used for the initial stellar composition.