Orbital radius during the grazing envelope evolution

TL;DR

This study uses the MESA code to explore how jets from a secondary star can strip an AGB star's envelope, potentially preventing a common envelope phase and influencing binary star evolution.

Contribution

It introduces the concept of grazing envelope evolution driven by jets and assesses its conditions and implications in binary star systems.

Findings

GEE can occur instead of common envelope phase in many cases.

Jet-driven mass removal can significantly alter binary evolution pathways.

Further studies needed to define the parameter space for GEE.

Abstract

We use the binary module of the MESA code to study the evolution of an evolved binary system where we assume that a main sequence companion removes the outskirts of the envelope of an asymptotic giant branch (AGB) star by launching jets, and explore the characteristics of this grazing envelope evolution (GEE). We base our assumption that jets launched by the secondary star remove a substantial fraction of the outskirts of the envelope of an AGB star on earlier hydrodynamical simulations. We find that in many cases that we study, but not in all cases, the binary system experiences the GEE rather than entering the common envelope phase, under our assumptions of jet-driven mass removal. To prevent the common envelope phase, we assume the secondary star may accrete a large amount of mass in a short time while avoiding rapid inflation, the feasibility of which requires further study. Because of our simplifying assumptions we cannot yet present the parameter space for the GEE. Although the incorporation of the GEE into population synthesis numerical codes requires further studies of the GEE, we conclude that analyses of population synthesis studies of evolved binary stars should include the GEE.