The Brown Dwarf-Exoplanet Connection

TL;DR

This paper reviews the similarities and differences between brown dwarf and exoplanet atmospheres, highlighting how brown dwarf studies can inform future exoplanet research despite key physical distinctions.

Contribution

It provides a comprehensive comparison of brown dwarf and exoplanet atmospheric properties, emphasizing their differences and potential relevance for exoplanet observations.

Findings

Brown dwarfs and exoplanets share similar atmospheric temperatures.

Differences include gas pressures, elemental abundances, and external influences.

Brown dwarf studies offer insights for future exoplanet research.

Abstract

Brown dwarfs are commonly regarded as easily-observed templates for exoplanet studies, with comparable masses, physical sizes and atmospheric properties. There is indeed considerable overlap in the photospheric temperatures of the coldest brown dwarfs (spectral classes L and T) and the hottest exoplanets. However, the properties and processes associated with brown dwarf and exoplanet atmospheres can differ significantly in detail; photospheric gas pressures, elemental abundance variations, processes associated with external driving sources, and evolutionary effects are all pertinent examples. In this contribution, I review some of the basic theoretical and empirical properties of the currently known population of brown dwarfs, and detail the similarities and differences between their visible atmospheres and those of extrasolar planets. I conclude with some specific results from brown dwarf studies that may prove relevant in future exoplanet observations.