Thermonuclear reaction rate of Si 30 (p,γ) P 31

Silicon synthesis in high-temperature hydrogen burning environments presents one possible avenue for the study of abundance anomalies in globular clusters. This was suggested in a previous study, which found that the large uncertainties associated with the Si30(p,γ)P31 reaction rate preclude a firm understanding of the stellar conditions that give rise to the Mg-K anticorrelation observed in the globular cluster NGC 2419. In an effort to improve the reaction rate, we present new strength measurements of the Erlab=435 keV and Erlab=501 keV resonances in Si30(p,γ)P31. For the former, which was previously unobserved, we obtain a resonance strength of ωγ=(1.14±0.25) ×10-4 eV. For the latter, we obtain a value of ωγ=(1.88±0.14) ×10-1 eV, which has a smaller uncertainty compared to previously measured strengths. Based on these results, the thermonuclear reaction rate has been re-evaluated. The impact of the new measurements is to lower the reaction rate by a factor of ≈10 at temperatures important to the study of NGC 2419. The rate uncertainty at these temperatures has also been reduced significantly