Fox W, Longland R, Marshall C, Chaves FP. High Resolution Study of ^{40}Ca to Constrain Potassium Nucleosynthesis in NGC 2419.
PHYSICAL REVIEW LETTERS 2024;
132:062701. [PMID:
38394582 DOI:
10.1103/physrevlett.132.062701]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/28/2023] [Accepted: 01/10/2024] [Indexed: 02/25/2024]
Abstract
The globular cluster NGC 2419 was the first to exhibit a Mg-K anticorrelation, linked to hydrogen burning at temperatures between 80-260 MK. However, the key K-destroying reaction, ^{39}K(p,γ)^{40}Ca, has a large rate uncertainty in this range. We significantly constrain this rate with a high resolution ^{39}K(^{3}He,d)^{40}Ca study. We resolve the E_{r}^{c.m.}=154 keV resonance in ^{39}K+p for the first time, increasing the previous rate by up to a factor 13 and reducing its 1σ width by up to a factor of 42. Reaction network calculations for NGC 2419 suggest that this could lower temperatures needed to reproduce the Mg-K anticorrelation.
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