New energy for the 133-keV resonance in the 23Na(p, γ) 24Mg reaction and its impact on nucleosynthesis in globular clusters

Globular cluster stars exhibit star-to-star anticorrelations between oxygen and sodium in their atmospheres. An improved description of the sodium-destroying Na-23+p reaction rates is essential to understanding these observations. We present an energy analysis of Mg-24 states based on a new measurement of the Na-23(He-3, d) Mg-24 reaction. A key resonance in Na-23(p, gamma) Mg-24 is found to be at E-r(c.m) = 133(3) keV, 5 keV lower than previously adopted. This finding has a dramatic effect on the Na-23(p, gamma) Mg-24 reaction rate, increasing it by a factor of 2 for the recommended rate. The nucleosynthesis impact of this change is investigated.

Automated summary

The stars in globular clusters exhibit star-to-star anticorrelations between oxygen and sodium in their atmospheres. An energy analysis of Mg-24 states was conducted based on a new measurement of the Na-23(He-3, d) Mg-24 reaction. A key resonance in Na-23(p, gamma) Mg-24 was found to be at E-r(c.m) = 133(3) keV, 5 keV lower than previously assumed, leading to a significant increase in the reaction rate.