Electron fraction constraints based on Nuclear Statistical Equilibrium with beta equilibrium

TL;DR

This paper demonstrates that nuclear statistical equilibrium combined with beta equilibrium can serve as a model-independent method to constrain the electron fraction in various astrophysical environments, reducing uncertainties from nuclear physics calculations.

Contribution

It introduces a novel approach using nuclear statistical equilibrium with beta equilibrium to constrain electron fraction independently of nuclear physics uncertainties.

Findings

Validates the approximation in presupernova models

Provides lower limits for electron fraction in type Ia supernovae

Offers a new constraint method applicable across astrophysical scenarios

Abstract

The electron-to-nucleon ratio or electron fraction is a key parameter in many astrophysical studies. Its value is determined by weak-interaction rates that are based on theoretical calculations subject to several nuclear physics uncertainties. Consequently, it is important to have a model independent way of constraining the electron fraction value in different astrophysical environments. Here we show that nuclear statistical equilibrium combined with beta equilibrium can provide such a constraint. We test the validity of this approximation in presupernova models and give lower limits for the electron fraction in type Ia supernova and accretion-induced collapse.