Self-regulating jets during the Common Envelope phase

TL;DR

This study uses 3D hydrodynamic simulations to explore how self-regulating jets from compact objects influence the evolution and potential unbinding of common envelope systems, revealing conditions for jet-driven ejection.

Contribution

It provides the first detailed analysis of jet effects during the CE phase, showing how jet efficiency impacts accretion, unbinding, and system evolution.

Findings

Jets can unbind outer CE layers at sufficient efficiency.

Jet variability affects size and orientation during expansion.

High-efficiency jets can significantly alter the system's evolution.

Abstract

Jets launched from a compact object (CO) during a common envelope (CE) may play a key role in the evolution of the system, and may also be an efficient removal channel for its material. In this work we study, through a large set of three-dimensional hydrodynamic simulations, the effects that jets launched from either a black hole (BH) or a neutron star (NS) have during a CE phase. The jet is self-consistently powered by a fraction ($\eta$) of the mass accretion rate that reaches the CO. For low mass accretion efficiencies ($\eta$<0.1\%), the jet is not able to drill through the material accreting onto the CO and forms a bulge around it. For higher efficiencies, the jet is able to drill through the bulge and in intermediate efficiencies ($\eta \sim$1-5\%) may produce an oscillating mass accretion rate behavior. We find that the jet may deposit enough energy to unbind the outer layers of the CE. The self-regulated jets present variability in size and orientation while their cocoons expand smoothly over the CE. The mass accretion rate initially decreases due to the ram pressure of the cocoon. If the launched jet is not able to drill through the bulge, the accretion is such that it may convert a NS into a BH within a decade or double the mass of a BH in a few years. If a jet is present, it deposits enough energy to unbind the outer layers of the CE and the system evolves into a grazing envelope, configuration.