The cometary cavity created by an aligned streaming environment/collimated outflow interaction

TL;DR

This paper develops a simplified analytical model and performs numerical simulations to study how a biconical outflow interacts with a streaming environment aligned with its flow, relevant to structures like Mira's cometary tail.

Contribution

It introduces a 'thin shell' analytical model for outflow-streaming environment interactions and validates it with axisymmetric numerical simulations, applicable to astrophysical objects like Mira.

Findings

Analytic model agrees well with numerical simulations

Interaction region is broad and non-radiative

Applicable to observed bipolar outflows like Mira B

Abstract

We present a "thin shell" model of the interaction of a biconical outflow and a streaming environment (aligned with the direction of the flow), as well as numerical (axisymmetric) simulations of such an interaction. A similar situation, although in a more complex setup, takes place at the head of the cometary structure of Mira. Thus, for most of the numerical simulations we explore parameters consistent with the observed bipolar outflow from Mira B. For these parameters, the interaction is non-radiative, so that a rather broad jet/streaming environment interaction region is formed. In spite of this, a reasonable agreement between the thin-shell analytic model and the numerical simulations is obtained.