On the 14C(alpha,gamma) reaction rate

TL;DR

This paper refines the 14C(alpha,gamma) reaction rate at low temperatures by measuring resonance properties, impacting models of stellar evolution and nucleosynthesis in white dwarfs and AGB stars.

Contribution

It provides new alpha-transfer measurements of near-threshold resonances in 18O, leading to an improved reaction rate calculation for astrophysical models.

Findings

Revised 14C(alpha,gamma) reaction rate at temperatures below 0.3 GK.

Implications for helium white dwarf evolution and AGB nucleosynthesis.

Enhanced understanding of stellar nucleosynthesis processes.

Abstract

The 14C(alpha,gamma) reaction rate at temperatures below 0.3 GK depends on the properties of two near threshold resonances in 18O, the 1- at 6.198 MeV and the 3- at 6.404 MeV. The alpha+14C Asymptotic Normalization Coefficients (ANCs) for these resonances were determined using the alpha-transfer reactions 14C(7Li,t) and 14C(6Li,d) at sub-Coulomb energies. The 14C(alpha,gamma) reaction rate at low temperatures has been evaluated. Implications of the new reaction rate on the evolution of accreting helium white dwarfs and on the nucleosynthesis of low mass stars during the asymptotic giant branch (AGB) phase are discussed.