Expect the unexpected: non-equilibrium processes in brown dwarf atmospheres

TL;DR

This paper discusses the importance of non-equilibrium processes, such as cloud formation and ionization, in brown dwarf atmospheres, emphasizing the need for diverse models and attention to unexpected phenomena for accurate interpretation.

Contribution

It advocates for using multiple model families for parameter estimation and highlights the significance of non-equilibrium effects like ionization in brown dwarf atmospheres.

Findings

Cloud formation driven by phase-non-equilibrium processes

Ionization signatures indicating plasma processes

Recommendation to use diverse models for reliable parameters

Abstract

Brown Dwarf atmosphere are a chemically extremely rich, one example being the formation of clouds driven by the phase-non-equilibrium of the atmospheric gas. Cloud formation modelling is an integral part of any atmosphere simulation used to interpret spectral observations of ultra-cool objects and to determine fundamental parameters like log(g) and Teff. This proceeding to the workshop 'GAIA and the Unseen: The Brown Dwarf Question' first summarizes what a model atmosphere simulation is, and then advocates two ideas: A) The use of a multitude of model families to determine fundamental parameters with realistic confidence interval. B) To keep an eye on the unexpected, like for example, ionisation signatures resulting plasma processes