The impact of an updated $^{14}N(p,\gamma)^{15}O$ reaction rate on advanced evolutionary stages of low-mass stellar models

TL;DR

This study assesses how the updated $^{14}N(p,\, ext{ extgamma})^{15}O$ reaction rate influences various evolutionary phases of low-mass, metal-poor stars, notably reducing red giant branch lifetimes by about 7-8%.

Contribution

It provides the first detailed analysis of the effects of the new reaction rate on multiple stellar evolutionary features in low-mass stars.

Findings

Red giant branch lifetimes decrease by approximately 7-8%.

Luminosities of horizontal branch models are affected.

Predictions for the red giant branch tip luminosity align well with observations.

Abstract

We have investigated the impact of the $^{14}N(p,\gamma)^{15}O$ reaction rate recently redetermined by the LUNA experiment, on the shell H-burning and core He-burning phases of low-mass, metal poor stellar models. The new reaction rate has small but noticeable effects, the largest one being a $\sim$7-8\% reduction of the red giant branch lifetimes. To different degrees, the lifetimes and luminosities of horizontal branch models, the mass of the stellar models evolving within the RR Lyrae instability strip, the luminosity of the red giant branch luminosity function bump, the theoretical calibrations of the R-parameter and tip of the red giant branch luminosity are also affected. Predictions for the tip of the red giant branch luminosity, in particular, are in very good agreement with the currently available empirical constraints.