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Related papers: A Comparative L-dwarf Sample Exploring the Interpl…

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Bayesian atmospheric retrieval tools can place constraints on the properties of brown dwarfs and hot Jupiters atmospheres. To fully exploit these methods, high signal-to-noise spectral libraries with well-understood uncertainties are…

Understanding differences between sub-stellar spectral data and models has proven to be a major challenge, especially for self-consistent model grids that are necessary for a thorough investigation of brown dwarf atmospheres. Using the…

Solar and Stellar Astrophysics · Physics 2023-07-07 Anna Lueber , Daniel Kitzmann , Chloe E. Fisher , Brendan P. Bowler , Adam J. Burgasser , Mark Marley , Kevin Heng

We present a large forward-modeling analysis for 55 late-T (T7-T9) dwarfs, using low-resolution ($R\approx150$) near-infrared spectra and cloudless Sonora-Bobcat model atmospheres. We derive the objects' effective temperatures, surface…

Solar and Stellar Astrophysics · Physics 2021-11-17 Zhoujian Zhang , Michael C. Liu , Mark S. Marley , Michael R. Line , William M. J. Best

We present the discovery of 2MASS J11263991-5003550 identified as part of an ongoing survey to discover ultra-cool dwarfs in the Southern Galactic Plane, using data from the 2MASS and SuperCOSMOS Sky Surveys. Strong FeH and H2O absorption…

Astrophysics · Physics 2008-11-26 Stuart L. Folkes , David J. Pinfield , Tim R. Kendall , Hugh R. A. Jones.

We present an atmospheric retrieval analysis on a set of young, cloudy, red L-dwarfs -- CWISER J124332.12+600126.2 and WISEP J004701.06+680352.1 -- using the \textit{Brewster} retrieval framework. We also present the first elemental…

We present a library of near-infrared (1.1-2.45 microns) medium-resolution (R~1500-2000) integral field spectra of 15 young M6-L0 dwarfs, composed of companions with known ages and of isolated objects. We use it to (re)derive the NIR…

Solar and Stellar Astrophysics · Physics 2015-06-16 M. Bonnefoy , G. Chauvin , A. -M. Lagrange , P. Rojo , F. Allard , C. Pinte , C. Dumas , D. Homeier

We present 6300--10100 {\AA} spectra for a sample of 13 T dwarfs observed using LRIS mounted on the Keck I 10m Telescope. A variety of features are identified and analyzed, including pressure-broadened K I and Na I doublets; narrow Cs I and…

Astrophysics · Physics 2016-08-30 Adam J. Burgasser , J. Davy Kirkpatrick , James Liebert , Adam Burrows

We report an attempt to interpret the spectra of L and T dwarfs with the use of the Unified Cloudy Model (UCM). For this purpose, we extend the grid of the UCMs to the cases of log g = 4.5 and 5.5. The dust column density relative to the…

Astrophysics · Physics 2009-11-10 Takashi Tsuji , Tadashi Nakajima , Kenshi Yanagisawa

We present a forward-modeling framework using the Bayesian inference tool Starfish and cloudless Sonora-Bobcat model atmospheres to analyze low-resolution ($R\approx80-250$) near-infrared ($1.0-2.5$ $\mu$m) spectra of T dwarfs. Our approach…

Solar and Stellar Astrophysics · Physics 2021-08-04 Zhoujian Zhang , Michael C. Liu , Mark S. Marley , Michael R. Line , William M. J. Best

We present the distance-calibrated spectral energy distribution (SED) of the d/sdL7 SDSS J14162408+1348263A (J1416A) and an updated SED for SDSS J14162408+1348263B (J1416B). We also present the first retrieval analysis of J1416A using the…

Solar and Stellar Astrophysics · Physics 2022-09-07 Eileen Gonzales , Ben Burningham , Jackie Faherty , Colleen Cleary , Channon Visscher , Mark Marley , Roxana Lupu , Richard Freedman

By comparing near-infrared spectra with atmosphere models, we infer the effective temperature, surface gravity, projected rotational velocity, and radial velocity for 21 very-low-mass stars and brown dwarfs. The unique sample consists of…

Solar and Stellar Astrophysics · Physics 2014-11-20 Emily L. Rice , T. Barman , Ian S. McLean , L. Prato , J. Davy Kirkpatrick

We test state-of-the-art model atmospheres for young very low-mass stars and brown dwarfs in the infrared, by comparing the predicted synthetic photometry over 1.2-24 {\mu}m to the observed photometry of M-type spectral templates in…

Solar and Stellar Astrophysics · Physics 2015-05-27 Jonathan Tottle , Subhanjoy Mohanty

We determine the effective temperature, surface gravity and projected rotational velocity of nine T dwarfs from the comparison of high-resolution near-infrared spectra and synthetic models, and estimate the mass and age of the objects from…

Solar and Stellar Astrophysics · Physics 2015-05-13 C. del Burgo , E. L. Martin , M. R. Zapatero Osorio , P. H. Hauschildt

(Abridged) We present a systematic assessment of two major cloudy atmospheric model grids -- SM08 (Saumon & Marley 2008) and Sonora Diamondback -- when applied to low-resolution near-infrared (0.8-2.5 $\mu$m) spectroscopy. Our analysis…

We describe advances on a method designed to derive accurate parameters of M dwarfs. Our analysis consists in comparing high-resolution infrared spectra acquired with the near-infrared spectro-polarimeter SPIRou to synthetic spectra…

Solar and Stellar Astrophysics · Physics 2022-09-28 P. I. Cristofari , J. -F. Donati , T. Masseron , P. Fouqué , C. Moutou , A. Carmona , E. Artigau , E. Martioli , G. Hébrard , E. Gaidos , X. Delfosse

Context: L-type ultra-cool dwarfs and brown dwarfs have cloudy atmospheres that could host weather-like phenomena. The detection of photometric or spectral variability would provide insight into unresolved atmospheric heterogeneities, such…

This paper describes the discovery of seven dwarf objects of spectral type `L' (objects cooler than the latest M dwarfs) in commissioning imaging data taken by the Sloan Digital Sky Survey (SDSS). Low-resolution spectroscopy shows that…

Astrophysics · Physics 2009-10-31 SDSS Collaboration , Xiaohui Fan

The complexity of atmospheric retrieval models is largely data-driven and one-dimensional models have generally been considered adequate with current data quality. However, recent studies have suggested that using 1D models in retrievals…

Earth and Planetary Astrophysics · Physics 2022-07-20 Luis Welbanks , Nikku Madhusudhan

We present a comparison of low-resolution spectra of 60 stars covering the whole M-dwarf sequence. Using the most recent PHOENIX BT-Settl stellar model atmospheres (see paper by F. Allard, in this book) we do a first quantitative compari-…

Solar and Stellar Astrophysics · Physics 2011-02-09 C. Reyle , A. S. Rajpurohit , M. Schultheis , F. Allard

Clouds of metal-bearing condensates play a critical role in shaping the emergent spectral energy distributions of the coolest classes of low-mass stars and brown dwarfs, L and T dwarfs. Because condensate clouds in planetary atmospheres…