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

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 ³⁰Si(p ,γ )³¹P 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 E_r^lab=435 keV and E_r^lab=501 keV resonances in ³⁰Si(p ,γ )³¹P . For the former, which was previously unobserved, we obtain a resonance strength of ω γ =(1.14 ±0.25 ) ×10^-4 eV. For the latter, we obtain a value of ω γ =(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.