Going from 3D common-envelope simulations to fast 1D simulations

TL;DR

This paper introduces a 1D simulation method for the common-envelope phase, demonstrating its ability to replicate 3D simulation results across different stellar masses efficiently.

Contribution

The paper extends a 1D CE simulation method to massive stars, showing it can match 3D results by adjusting free parameters based on stellar structure.

Findings

1D model reproduces orbital evolution and envelope ejection.

Free parameters depend on the giant star's structure.

Recombination energy aids envelope expansion.

Abstract

One-dimensional (1D) methods for simulating the common-envelope (CE) phase offer advantages over three-dimensional (3D) simulations regarding their computational speed and feasibility. We present the 1D CE method from Bronner et al. (2024), including the results of the CE simulations of an asymptotic giant branch star donor. We further test this method in the massive star regime by computing the CE event of a red supergiant with a neutron-star mass and a black-hole mass companion. The 1D model can reproduce the orbital evolution and the envelope ejection from 3D simulations when choosing suitable values for the free parameters in the model. The best-fitting values differ from the expectations based on the low mass simulations, indicating that the free parameters depend on the structure of the giant star. The released recombination energy from hydrogen and helium helps to expand the envelope, similar to the low-mass CE simulations.