Stability of an Ionization Front in Bondi Accretion

TL;DR

This paper investigates the hydrodynamic stability of two-phase ionized and neutral accretion flows in astrophysics, revealing that their stability depends on initial conditions and the nature of ionization fronts.

Contribution

It provides a combined semi-analytic and numerical analysis of the stability of two-phase Bondi accretion flows, highlighting the role of ionization front transitions.

Findings

Flows can be stable, conditionally stable, or unstable.

The transition from R-type to D-type ionization front influences stability.

Stability depends on initial conditions and ionization front dynamics.

Abstract

Spherical Bondi accretion is used in astrophysics as an approximation to investigate many types of accretion processes. Two-phase accretion flows that transition from neutral to ionized have observational support in high-mass star formation, and have application to accretion flows around any ionizing source, but the hydrodynamic stability of two-phase Bondi accretion is not understood. With both semi-analytic and fully numerical methods we find that these flows may be stable, conditionally stable or unstable depending on the initial conditions. The transition from an R-type to a D-type ionization front plays a key role in conditionally stable and unstable flows.