A Survey Of Model Fits to Brown Dwarf Spectra Through the L-T Sequence

TL;DR

This survey analyzes near-infrared spectra of 305 brown dwarfs using atmosphere models to understand their atmospheric evolution, cloud impacts, and spectral diversity, highlighting model-data agreements and discrepancies.

Contribution

It provides a comprehensive survey of brown dwarf atmospheres across the L-T sequence, identifying cloud effects and spectral families, including potential binaries, based on model fits.

Findings

Clouds significantly affect near-infrared spectra more than disequilibrium chemistry.

Silicate clouds influence late T dwarf spectra.

Identified spectral families possibly indicating binarity.

Abstract

We fit archival near-infrared spectra of 305 brown dwarfs with atmosphere models from the Sonora and Phoenix groups. Using the parameters of the best-fit models as estimates for the physical properties of the brown dwarfs in our sample, we have performed a survey of how brown dwarf atmospheres evolve with spectral type and temperature. We present the fit results and observed trends. We find that clouds have a more significant impact on near infrared spectra than disequilibrium chemistry, and that silicate clouds influence the near infrared spectrum through the late T types. We note where current atmosphere models are able to replicate the data and where the models and data conflict. We also categorize objects with similar spectral morphologies into families and discuss possible causes for their unique spectral traits. We identify two spectral families with morphologies that are likely indicative of binarity.