Reducing Uncertainties in the Production of the Gamma-emitting Nuclei Al-26, Ti-44, and Fe-60 in Core-collapse Supernovae by Using Effective Helium Burning Rates

摘要

We have used effective reaction rates (ERRs) for the helium burning reactions to predict the yield of the gamma-emitting nuclei Al-26, Ti-44, and Fe-60 in core-collapse supernovae (SNe). The variations in the predicted yields for values of the reaction rates allowed by the ERR are much smaller than obtained previously, and smaller than other uncertainties. A "filter" for SN nucleosynthesis yields based on pre-SN structure was used to estimate the effect of failed SNe on the initial mass function averaged yields; this substantially reduced the yields of all these isotopes, but the predicted yield ratio Fe-60/Al-26 was little affected. The robustness of this ratio is promising for comparison with data, but it is larger than observed in nature; possible causes for this discrepancy are discussed.