English
Related papers

Related papers: Intercomparison of Brown Dwarf Model Grids and Atm…

200 papers

Irradiated brown dwarfs (BDs) provide natural laboratories to test our understanding of substellar and irradiated atmospheres. A handful of short-period BDs around white dwarfs (WDs) have been observed, but the uniquely intense UV-dominated…

Solar and Stellar Astrophysics · Physics 2021-01-06 Joshua D. Lothringer , Sarah L. Casewell

Brown dwarf spectra offer vital testbeds for our understanding of the chemical and physical processes that sculpt substellar atmospheres. Recently, atmospheric retrieval approaches have been applied to a number of low-resolution (R~100)…

Solar and Stellar Astrophysics · Physics 2023-07-12 Callie E. Hood , Jonathan J. Fortney , Michael R. Line , Jacqueline K. Faherty

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 present results from an atmospheric retrieval analysis of Gl 229B using the BREWSTER retrieval code. We find the best fit model to be cloud-free, consistent with the T dwarf retrieval work of Line et al. 2017, Zalesky et al. 2022 and…

Isolated brown dwarfs provide remarkable laboratories for understanding atmospheric physics in the low-irradiation regime, and can be observed more precisely than exoplanets. As such, they provide a glimpse into the future of high-SNR…

Earth and Planetary Astrophysics · Physics 2020-09-02 Anjali A. A. Piette , Nikku Madhusudhan

Comparisons of atmospheric retrievals can reveal powerful insights on the strengths and limitations of our data and modeling tools. In this paper, we examine a sample of 5 similar effective temperature (Teff) or spectral type L dwarfs to…

Earth and Planetary Astrophysics · Physics 2022-10-26 Eileen C. Gonzales , Ben Burningham , Jacqueline K. Faherty , Nikole K. Lewis , Channon Visscher , Mark Marley

A large suite of 228 atmospheric retrievals is performed on a curated sample of 19 brown dwarfs spanning the L0 to T8 spectral types using the open-source Helios-r2 retrieval code, which implements the method of short characteristics for…

Earth and Planetary Astrophysics · Physics 2022-05-18 Anna Lueber , Daniel Kitzmann , Brendan P. Bowler , Adam J. Burgasser , Kevin Heng

The James Webb Space Telescope (JWST) offers exceptional spectral resolution and wavelength coverage, which are essential for studying the coldest brown dwarfs, particularly Y dwarfs. These objects are at the cold end of the sub-stellar…

Solar and Stellar Astrophysics · Physics 2026-01-21 A. Lueber , D. Kitzmann , K. Heng

In modern astrophysics, the machine learning has increasingly gained more popularity with its incredibly powerful ability to make predictions or calculated suggestions for large amounts of data. We describe an application of the supervised…

Astrophysics of Galaxies · Physics 2018-12-26 Yu Bai , JiFeng Liu , Song Wang , Fan Yang

We present a new method for performing atmospheric retrieval on ground-based, high-resolution data of exoplanets. Our method combines cross-correlation functions with a random forest, a supervised machine learning technique, to overcome…

Earth and Planetary Astrophysics · Physics 2020-04-15 Chloe Fisher , H. Jens Hoeijmakers , Daniel Kitzmann , Pablo Márquez-Neila , Simon L. Grimm , Raphael Sznitman , Kevin Heng

Brown dwarfs provide a unique opportunity to study atmospheres and their physical and chemical processes with high precision, especially in temperature ranges relevant to exoplanets. In this study, we performed high-resolution ($R \sim…

The alfalfa crop is globally important as livestock feed, so highly efficient planting and harvesting could benefit many industries, especially as the global climate changes and traditional methods become less accurate. Recent work using…

Machine Learning · Computer Science 2022-10-21 Jonathan Vance , Khaled Rasheed , Ali Missaoui , Frederick Maier , Christian Adkins , Chris Whitmire

We present a new suite of atmosphere models with flexible cloud parameters to investigate the effects of clouds on brown dwarfs across the L/T transition. We fit these models to a sample of 13 objects with well-known masses, distances, and…

Solar and Stellar Astrophysics · Physics 2021-06-21 Laci Shea Brock , Travis Barman , Quinn M. Konopacky , Jordan M. Stone

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…

Astrophysics · Physics 2007-05-23 D. Saumon , M. S. Marley , K. Lodders

We present the first results from applying the spectral inversion technique in the cloudy L dwarf regime. Our new framework provides a flexible approach to modelling cloud opacity which can be built incrementally as the data requires, and…

Context: Brown dwarfs exhibit complex atmospheric signatures, and their properties depend sensitively on effective temperature, surface gravity, and metallicity. Several physical properties of brown dwarfs in binary systems can be well…

Astrophysics · Physics 2009-11-13 K. Geißler , G. Chauvin , M. F. Sterzik

We present a method for measuring the physical parameters of the coldest T-type brown dwarfs using low resolution near infrared spectra. By comparing H_2O- and H_2-sensitive spectral ratios between empirical data and theoretical atmosphere…

Astrophysics · Physics 2009-11-13 Adam J. Burgasser , Adam Burrows , J. Davy Kirkpatrick

Temperature fluctuations significantly affect microorganism growth and pest activities in grain pile, precise monitoring and forecasting temperature of stored grain are essential for maintaining the quality and safety of grain storage. This…

Computational Engineering, Finance, and Science · Computer Science 2024-04-18 Donghao Chen , Binkun Liu

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…

Constraining L dwarf properties from their spectra is challenging. Near-infrared spectra probe a limited range of pressures, while many species condense within their photospheres. Condensation creates two complexities: gas-phase species…

Solar and Stellar Astrophysics · Physics 2023-04-19 Melanie Rowland , Caroline Morley , Michael Line