Dynamical Opacity-Sampling Models of Mira Variables. II: Time-Dependent Atmospheric Structure and Observable Properties of 4 M-Type Model Series

TL;DR

This paper introduces four series of dynamical models for Mira variables that accurately simulate their atmospheric structures and observable properties, enhancing understanding of their molecular shells and wind-driving mechanisms.

Contribution

The study develops and validates new time-dependent dynamical models of Mira atmospheres, linking molecular shell phenomena to observable photometric and interferometric data.

Findings

Models match observed photometry and interferometry across wavelengths

Fe-poor silicate grains are too small to drive stellar winds

Models provide physical basis for molecular shell explanations

Abstract

We present 4 model series of the CODEX dynamical opacity-sampling models of Mira variables with solar abundances, designed to have parameters similar to $o$ Cet, R Leo and R Cas. We demonstrate that the CODEX models provide a clear physical basis for the molecular shell scenario used to explain interferometric observations of Mira variables. We show that these models generally provide a good match to photometry and interferometry at wavelengths between the near-infrared and the radio, and make the model outputs publicly available. These model also demonstrate that, in order to match visible and infrared observations, the Fe-poor silicate grains that form within 3 continuum radii must have small grain radii and therefore can not drive the winds from O-rich Mira variables.