Impact of Coulomb Correction Factor on Rate of Change of Lepton Fraction during Presupernova Evolution

TL;DR

This study revisits the impact of Coulomb correction factors on lepton fraction changes during presupernova evolution, revealing significant enhancements in nuclear abundances and updated Ye intervals affecting stellar core collapse models.

Contribution

It introduces a revised calculation of nuclear abundances and lepton fractions incorporating Coulomb corrections, refining previous models of presupernova stellar evolution.

Findings

Coulomb corrections increase heavy nuclei abundances by up to 3 orders of magnitude.

The Ye interval where beta decay dominates is revised to 0.423–0.455.

Total Ye and Yb values are increased by Coulomb effects, impacting supernova modeling.

Abstract

We reexamine the weak interaction nuclei having largest contribution to the lepton to baryon fraction Ye by coupling the stellar weak rates and mass abundances for post silicon burning conditions during the presupernova evolution of massive stars. The stellar weak rates were recently calculated by Nabi et al. 2021 employing the fully microscopic pnQRPA model without invoking the Brink Axel hypothesis. We compute the mass abundances for a total of 728 nuclei, with A equal 1to 100, using Sahas equation and assuming nuclear statistical equilibrium with the incorporation of Coulomb correction factor to the chemical potential. We compile a list of top 50 electron capture ec and \b{eta} decay bd nuclei on the basis of largest contribution to Ye forpost silicon burning conditions where 11 percent ec and 6percent bd nuclei debuted dueto Coulomb corrections. The calculated mass abundances and corresponding Ye values are enhanced up to 3 orders of magnitude for heavier nuclei once Coulomb corrections were incorporated. This enhancement led to anincrement in total Y bde and Yece values, at Ye equal to 0.425 (\r{ho} equal 2.20 multiply 109 g/cm3 of 80percent and 91percent respectively. After incorporating the Coulomb corrections we propose a revised interval of Ye equal 0.423 0.455 where bd rates surpass thecompeting ec rates and is 3.2 percent bigger than the one suggested by Nabi et al. (2021).