Numerical simulation of common envelope stage in close binary systems: comparison between Newtonian and modified gravity

TL;DR

This paper uses numerical simulations to compare the common envelope phase in close binary systems under Newtonian and modified gravity models, exploring potential observational differences over long timescales.

Contribution

It introduces a method to incorporate modified gravity into the AREPO code and compares the evolution of binary systems in both gravity frameworks.

Findings

Modified gravity causes negligible immediate differences from Newtonian predictions.

Long-term effects of modified gravity may lead to observable imprints.

Simulations show similar initial orbital decay in both models.

Abstract

We consider the important stage in evolution of close binary system namely common envelope phase in framework of various models of modified gravity. The comparison of results between calculations in Newtonian gravity and modified gravity allows to estimate possible observational imprints of modified gravity. Although declination from Newtonian gravity should be negligible we can propose that due to the long times some new effects can appear. We use the moving-mesh code AREPO for numerical simulation of binary system consisting of $\sim M_{\odot}$ white dwarf and a red giant with mass $\sim 2 M_{\odot}$. For implementing modified gravity into AREPO code we apply the method of (pseudo)potential, assuming that modified gravity can be described by small corrections to usual Newtonian gravitational potential. As in Newtonian case initial orbit has to shrink due to the energy transfer to the envelope of a giant. We investigated evolution of common envelope in a case of simple model of modified gravity with various values of parameters and compared results with simulation in frames of Newtonian gravity.