Impact of newly measured 26Al(n, p)26Mg and 26Al(n, α)23Na reaction rates on the nucleosynthesis of 26Al in stars

The cosmic production of the short-lived radioactive nuclide Al-26 is crucial for our understanding of the evolution of stars and galaxies. However, simulations of the stellar sites producing Al-26 are still weakened by significant nuclear uncertainties. We re-evaluate the Al-26(n, p)Mg-26, and Al-26(n, alpha)Na-23 ground state reactivities from 0.01 GK to 10 GK, based on the recent n_TOF measurement combined with theoretical predictions and a previous measurement at higher energies, and test their impact on stellar nucleosynthesis. We computed the nucleosynthesis of low- and high-mass stars using the Monash nucleosynthesis code, the NuGrid mppnp code, and the FUNS stellar evolutionary code. Our low-mass stellar models cover the 2-3 M-circle dot mass range with metallicities between Z = 0.01 and 0.02, their predicted Al-26/Al-27 ratios are compared to 62 meteoritic SiC grains. For high-mass stars, we test our reactivities on two 15 M-circle dot models with Z = 0.006 and 0.02. The new reactivities allow low-mass AGB stars to reproduce the full range of Al-26/Al-27 ratios measured in SiC grains. The final Al-26 abundance in high-mass stars, at the point of highest production, varies by a factor of 2.4 when adopting the upper, or lower limit of our rates. However, stellar uncertainties still play an important role in both mass regimes. The new reactivities visibly impact both low- and high-mass stars nucleosynthesis and allow a general improvement in the comparison between stardust SiC grains and low-mass star models. Concerning explosive nucleosynthesis, an improvement of the current uncertainties between T9 similar to 0.3 and 2.5 is needed for future studies.