A model of Mira's cometary head/tail entering the Local Bubble

TL;DR

This paper models Mira's cometary structure as an interaction between its stellar wind and the Local Bubble environment, revealing how the head expands rapidly while the tail remains collimated, matching observations.

Contribution

It introduces a new simulation approach incorporating Mira's transition into the Local Bubble, explaining the observed cometary morphology with adaptive grid modeling.

Findings

The comet head expands rapidly upon entering the Local Bubble.

The tail remains collimated for about 100 kyr.

Simulation results match observed Mira comet structure.

Abstract

We model the cometary structure around Mira as the interaction of an AGB wind from Mira A, and a streaming environment. Our simulations introduce the following new element: we assume that after 200 kyr of evolution in a dense environment Mira entered the Local Bubble (low density coronal gas). As Mira enters the bubble, the head of the comet expands quite rapidly, while the tail remains well collimated for a 100 kyr timescale. The result is a broad-head/narrow-tail structure that resembles the observed morphology of Mira's comet. The simulations were carried out with our new adaptive grid code WALICXE, which is described in detail.