# Companion-launched jets and their effect on the dynamics of common envelope interaction simulations

## TL;DR

This study uses 3D hydrodynamic simulations to demonstrate that jets launched by a companion star during common envelope interactions significantly enhance envelope ejection, alter orbital dynamics, and shape outflows.

## Contribution

First simulation to include jets and gravitational energy in common envelope interactions, showing jets can substantially increase envelope unbinding and influence binary evolution.

## Key findings

- Jets unbind about three times more envelope mass.
- Jets produce high-velocity polar outflows.
- Jets increase the final orbital separation and system velocity.

## Abstract

We conduct three-dimensional hydrodynamic simulations of the common envelope binary interaction and show that if the companion were to launch jets while interacting with the giant primary star's envelope, the jets would remove a substantial fraction of the envelope's gas. We use the setup and numerical code of an earlier common envelope study that did not include jets, with a 0.88Mo, 83Ro red giant star and a 0.3Mo companion. The assumption is that the companion star accretes mass via an accretion disk that is responsible for launching the jets which, in the simulations, are injected numerically. For the first time we conduct simulations that include jets as well as the gravitational energy released by the inspiraling core-companion system. We find that simulations with jets unbind approximately three times as much envelope mass than identical simulations that do not include jets, though the total fraction of unbound gas remains below 50 per cent for these particular simulations. The jets generate high velocity outflows in the polar directions. The jets also increase the final core-companion orbital separation and lead to a kick velocity of the core-companion binary system. Our results show that, if able to form, jets could play a crucial role in ejecting the envelope and in shaping the outflow.