The Mid-Infrared Spectra of Brown Dwarfs

TL;DR

This paper analyzes mid-infrared spectra of brown dwarfs to enhance understanding of their atmospheric composition and chemistry, aiding future observations with the Space Infrared Telescope Facility.

Contribution

It provides detailed model spectra in the mid-infrared, highlighting diagnostics for atmospheric chemistry, cloud detection, and potential new molecular species.

Findings

Mid-infrared spectra are simpler than near-infrared but highly diagnostic.

Predicted detection of silicate clouds and non-equilibrium chemistry signatures.

Potential to discover brown dwarf stratospheres.

Abstract

We present an analysis of brown dwarf model spectra in the mid-infrared spectral region (5 - 20 microns), in anticipation of data obtained with the Space Infrared Telescope Facility. The mid-infrared spectra of brown dwarfs are in several ways simpler than those in the near-infrared and yet provide powerful diagnostics of brown dwarf atmospheric physics and chemistry, especially when combined with ground-based data. We discuss the possibility of detection of new molecular species and of the silicate cloud, predict strong observational diagnostics for non-equilibrium chemistry between CO and CH4, and N2 and NH3, and speculate on the possibility of discovering brown dwarf stratospheres.