Mass Loss Evolution and the Formation of Detached Shells around TP-AGB Stars

TL;DR

This paper presents a detailed model linking stellar evolution and mass loss processes to explain the formation of detached shells around TP-AGB stars, integrating eruptive events and wind interactions.

Contribution

It introduces a comprehensive, detailed model of mass loss and stellar evolution that explains detached shell formation, improving upon previous approximate methods.

Findings

Detached shells can form through combined eruptive mass loss and wind interaction.

The model aligns well with observational data.

Provides a detailed physical mechanism for shell formation.

Abstract

The origin of the so called 'detached shells' around AGB stars is not fully understood, but two common hypotheses state that these shells form either through the interaction of distinct wind phases or an eruptive mass loss associated with a He-shell flash. We present a model of the formation of detached shells around thermal pulse asymptotic giant branch (TP-AGB) stars, based on detailed modelling of mass loss and stellar evolution, leading to a combination of eruptive mass loss and wind interaction. The purpose of this paper is first of all to connect stellar evolution with wind and mass loss evolution and demonstrate its consistency with observations, but also to show how thin detached shells around TP-AGB stars can be formed. Previous attempts to link mass loss evolution with the formation of detached shells were based on approximate prescriptions for the mass loss and have not included detailed modelling of the wind formation as we do here. (abridged)