The Effects of the pep Nuclear Reaction and Other Improvements in the Nuclear Reaction Rate Library on Simulations of the Classical Nova Outburst

TL;DR

This study investigates how updated nuclear reaction rates, including the pep reaction, influence the characteristics of classical nova outbursts, affecting ejected mass, luminosity, and nucleosynthesis through improved hydrodynamic simulations.

Contribution

The paper introduces a modern nuclear reaction network into nova simulations and highlights the significant impact of the pep reaction on outburst evolution and observable features.

Findings

Updated reaction rates alter ejected mass and luminosity.

Inclusion of the pep reaction reduces the accreted mass before outburst.

Energy generation increases, affecting nova evolution timescales.

Abstract

We have continued our studies of the Classical Nova outburst by evolving TNRs on 1.25Msun and 1.35Msun WDs (ONeMg composition) under conditions which produce mass ejection and a rapid increase in the emitted light, by examining the effects of changes in the nuclear reaction rates on both the observable features and the nucleosynthesis during the outburst. In order to improve our calculations over previous work, we have incorporated a modern nuclear reaction network into our hydrodynamic computer code. We find that the updates in the nuclear reaction rate libraries change the amount of ejected mass, peak luminosity, and the resulting nucleosynthesis. In addition, as a result of our improvements, we discovered that the pep reaction was not included in our previous studies of CN explosions. Although the energy production from this reaction is not important in the Sun, the densities in WD envelopes can exceed $10^4$ gm cm$^{-3}$ and the presence of this reaction increases the energy generation during the time that the p-p chain is operating. The effect of the increased energy generation is to reduce the evolution time to the peak of the TNR and, thereby, the accreted mass as compared to the evolutionary sequences done without this reaction included. As expected from our previous work, the reduction in accreted mass has important consequences on the characteristics of the resulting TNR and is discussed in this paper.