The Sonora Brown Dwarf Atmosphere and Evolution Models I. Model Description and Application to Cloudless Atmospheres in Rainout Chemical Equilibrium

Abstract

We present a new generation of substellar atmosphere and evolution models, appropriate for application to studies of L, T, and Y-type brown dwarfs and self-luminous extrasolar planets. The atmosphere models describe the expected temperature-pressure profiles and emergent spectra of atmospheres in radiative-convective equilibrium with effective temperatures and gravities within the ranges $200\le T_{\mathrm{eff}}\le 2400\mathrm{K}$ and $2.5\le \log g\le 5.5$. These ranges encompass masses from about 0.5 to 85 Jupiter masses for a set of metallicities ($[M/H]=-0.5$ to $+0.5$), C/O ratios (from 0.5 to 1.5 times that of solar), and ages. The evolution tables describe the cooling of these substellar objects through time. These models expand the diversity of model atmospheres currently available, notably to cooler effective temperatures and greater ranges in C/O. Notable improvements from past such models include updated opacities and atmospheric chemistry. Here we describe our modeling approach and present our initial tranche of models for cloudless, chemical equilibrium atmospheres. We compare the modeled spectra, photometry, and evolution to various datasets.

27 pages, 16 figures, accepted for Astrophysical Journal. Models available at https://doi.org/10.5281/zenodo.5063476

References in corpus (41)

• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• The Evolution of L and T Dwarfs in Color-Magnitude Diagrams
• On the Luminosity of Young Jupiters
• Line and Mean Opacities for Ultracool Dwarfs and Extrasolar Planets
• The 0.8-14.5 micron Spectra of Mid-L to Mid-T Dwarfs: Diagnostics of Effective Temperature, Grain Sedimentation, Gas Transport, and Surface Gravity
• Synthetic Spectra and Colors of Young Giant Planet Atmospheres: Effects of Initial Conditions and Atmospheric Metallicity
• The Hawaii Infrared Parallax Program. II. Young Ultracool Field Dwarfs
• ExoMol line lists XVIII. The high temperature spectrum of VO
• Water Clouds in Y Dwarfs and Exoplanets
• The Transit Light Curve Project. V. System Parameters and Stellar Rotation Period of HD 189733
• ExoMol line lists VII: The rotation-vibration spectrum of phosphine up to 1500 K
• Uniform Atmospheric Retrieval Analysis of Ultracool Dwarfs I: Characterizing Benchmarks, Gl570D and HD3651B
• The Field Substellar Mass Function Based on the Full-sky 20-pc Census of 525 L, T, and Y Dwarfs
• Theory for the Secondary Eclipse Fluxes, Spectra, Atmospheres, and Light Curves of Transiting Extrasolar Giant Planets
• A Systematic Study of Departures from Chemical Equilibrium in the Atmospheres of Substellar Mass Objects
• High temperature condensate clouds in super-hot Jupiter atmospheres
• ExoMol molecular line lists V: The ro-vibrational spectra of NaCl and KCl
• K-H_2 Quasi-molecular absorption detected in the T-dwarf epsilon Indi Ba
• Treatment of overlapping gaseous absorption with the correlated-k method in hot Jupiter and brown dwarf atmosphere models
• A Volume-Limited Sample of Ultracool Dwarfs. I. Construction, Space Density, and a Gap in the L/T Transition
• Age Determination in Upper Scorpius with Eclipsing Binaries
• New low-mass eclipsing binary systems in Praesepe discovered by K2
• Helios-r2 -- A new Bayesian, open-source retrieval model for brown dwarfs and exoplanet atmospheres
• The mass-radius relationship from solar-type stars to terrestrial planets: a review
• Observations of Disequilibrium CO Chemistry in the Coldest Brown Dwarfs
• Spectral Variability from the Patchy Atmospheres of T and Y Dwarfs
• The Hawaii Infrared Parallax Program. IV. A Comprehensive Parallax Survey of L0-T8 dwarfs with UKIRT
• A Uniform Retrieval Analysis of Ultracool Dwarfs. III. Properties of Y-Dwarfs
• EPIC 219388192 b - an inhabitant of the brown dwarf desert in the Ruprecht 147 open cluster
• Two white dwarfs in ultrashort binaries with detached, eclipsing, likely substellar companions detected by K2
• The substellar companion in the eclipsing white dwarf binary SDSS J141126.20+200911.1
• A H13CN/HN13C linelist, model atmospheres and synthetic spectra for carbon stars
• The EBLM project III. A Saturn-size low-mass star at the hydrogen-burning limit
• WD1032+011, an inflated brown dwarf in an old eclipsing binary with a white dwarf
• Considerations for Atmospheric Retrieval of High-Precision Brown Dwarf Spectra
• Evolutionary models for ultracool dwarfs
• TOI 694 b and TIC 220568520 b: Two Low-Mass Companions Near the Hydrogen Burning Mass Limit Orbiting Sun-like Stars
• Analytical Models of Exoplanetary Atmospheres. IV. Improved Two-stream Radiative Transfer for the Treatment of Aerosols
• An eclipsing M-dwarf close to the hydrogen burning limit from NGTS
• Following the Lithium: Tracing Li-bearing Molecules Across Age, Mass, and Gravity in Brown Dwarfs