Constraint of the Astrophysical 26gAl(p,γ)27Si Destruction Rate at Stellar Temperatures

The Galactic 1.809-MeV gamma-ray signature from the beta decay of Al-26g is a dominant target of.-ray astronomy, of which a significant component is understood to originate from massive stars. The Al-26g(p,gamma)Si-27 reaction is a major destruction pathway for Al-26g at stellar temperatures, but the reaction rate is poorly constrained due to uncertainties in the strengths of low-lying resonances in Si-27. The Al-26g(d,p)Al-27 reaction has been employed in inverse kinematics to determine the spectroscopic factors, and hence resonance strengths, of proton resonances in Si-27 via mirror symmetry. The strength of the 127-keV resonance is found to be a factor of 4 higher than the previously adopted upper limit, and the upper limit for the 68-keV resonance has been reduced by an order of magnitude, considerably constraining the Al-26g destruction rate at stellar temperatures.