The impact of the uncertainties in the 12C({\alpha},{\gamma})16O reaction rate on the evolution of low- to intermediate-mass stars

TL;DR

This study investigates how uncertainties in the 12C(α,γ)16O reaction rate influence the evolution and final properties of low- to intermediate-mass stars, affecting core composition and white dwarf characteristics.

Contribution

It provides a comprehensive analysis of the impact of reaction rate uncertainties on stellar evolution using detailed MESA simulations across a range of initial masses.

Findings

Reaction rate uncertainties affect convective core mass during helium burning.

Variations influence the number of thermal pulses on the asymptotic giant branch.

Final oxygen abundance correlates with progenitor mass and reaction rate choice.

Abstract

One of the largest uncertainties in stellar evolutionary computations is the accuracy of the considered reaction rates. The 12C(alpha,gamma)16O reaction is particularly important for the study of low- and intermediate-mass stars as it determines the final C/O ratio in the core which influences the white dwarf cooling evolution. Thus, there is a need for a study of how the computations of white dwarfs and their progenitors that are made to date may be affected by the uncertainties of the 12C(alpha,gamma)16O reaction rates. In this work we compute fully evolutionary sequences using the MESA code with initial masses in the range of 0.90 <= Mi/Msun <= 3.05. We consider different adopted reaction rates, obtained from the literature, as well as the extreme limits within their uncertainties. As expected, we find that previous to the core helium burning stage there are no changes to the evolution of the stars. However, the subsequent stages are all affected by the uncertainties of the considered reaction rate. In particular, we find differences to the convective core mass during the core helium burning stage which may affect pulsation properties of subdwarfs, the number of thermal pulses during the asymptotic giant branch and trends between final oxygen abundance in the core and the progenitor masses of the remnant white dwarfs.