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

Recent photometric studies have revealed that surface spots that produce flux variations are present on virtually all L and T dwarfs. Their likely magnetic or dusty nature has been a much-debated problem, the resolution to which has been…

We have compiled L' and M' photometry of 63 single and binary M, L,and T dwarfs obtained at UKIRT using the MKO filter set. This compilation includes new L' data for 8 L dwarfs and 13 T dwarfs and new M' data for 7 L dwarfs, 5 T dwarfs, and…

2MASS 1207 b, the first directly imaged planetary-mass companion, has been instrumental in advancing our understanding of exoplanets and brown dwarfs over the past 20 years. We have performed extensive atmospheric retrieval analyses of…

In a previous paper we proposed a new model for the emission by amorphous astronomical dust grains, based on solid-state physics. The model uses a description of the Disordered Charge Distribution (DCD) combined with the presence of…

We present Spitzer 7.6-14.5um spectra of ULAS J003402.77-005206.7 and ULAS J133553.45+113005.2, two T9 dwarfs with the latest spectral types currently known. We fit synthetic spectra and photometry to the near- through mid-infrared energy…

Condensate clouds are a salient feature of L dwarf atmospheres, but have been assumed to play little role in shaping the spectra of the coldest T-type brown dwarfs. Here we report evidence of condensate opacity in the near-infrared spectrum…

The measurement of atmospheric parameters is fundamental for scientific research using stellar spectra. The Chinese Space Station Telescope (CSST), scheduled to be launched in 2024, will provide researchers with hundreds of millions of…

We present first results from a major program of methane filter photometry for low-mass stars and brown dwarfs. The definition of a new methane filter photometric system is described. A recipe is provided for the differential calibration of…

We estimated the spectral evolution of white dwarfs with effective temperature using the Javalambre Photometric Local Universe Survey (J-PLUS) second data release (DR2), that provides twelve photometric optical passbands over 2176 deg2. We…

We aim at developing an efficient method to search for late-type subdwarfs (metal-depleted dwarfs with spectral types >M5) to improve the current statistics. Our objectives are: improve our knowledge of metal-poor low-mass dwarfs, bridge…

Atmospheric retrieval determines the properties of an atmosphere based on its measured spectrum. The low signal-to-noise ratio of exoplanet observations require a Bayesian approach to determine posterior probability distributions of each…

In this study, the fundamental stellar atmospheric parameters (Teff, log g, [Fe/H] and [{\alpha}/Fe]) were derived for low-resolution spectroscopy from LAMOST DR5 with Generative Spectrum Networks (GSN). This follows the same scheme as a…

Large numbers of low-to-medium resolution spectra of M-type dwarf stars from both the local Galactic disk and halo are available from various surveys. In order to fully exploit these data, we develop a template-fit method using a set of…

Over a dozen T dwarfs, brown dwarfs that exhibit methane absorption features at 1.6 and 2.2 $\micron$, have been discovered by the 2MASS survey. We discuss how the search for these objects has been made, point out some of the limitations of…

We present the SPHEREx Ultracool Dwarf spectral Atlas (SUDA), a homogeneous sample of 1675 ultracool dwarfs with continuous 0.75--5 $\mu$m spectroscopy from SPHEREx QR2. Using the SAND and ATMO2020++ atmospheric model grids, we derive…

Using the Gemini infrared camera on the 3-meter Shane telescope at Lick Observatory, we have searched for broad-band J and K' photometric variability for a sample of 15 L and T-type brown dwarfs, including 7 suspected spectral binaries.…

This work aims to improve the current understanding of the atmospheres of brown dwarfs, especially cold ones with spectral type T and Y, whose modeling is a current challenge. Silicate and iron clouds are believed to disappear at the…

We present the discovery of fifteen new T2.5-T7.5 dwarfs (with estimated distances between ~24-93pc, identified in the first three main data releases of the UKIRT Infrared Deep Sky Survey. This brings the total number of T dwarfs discovered…

M dwarfs are the most abundant stars in the Solar Neighborhood and they are prime targets for searching for rocky planets in habitable zones. Consequently, a detailed characterization of these stars is in demand. The spectral sub-type is…

The coldest Y spectral type brown dwarfs are similar in mass and temperature to cool and warm ($\sim$200 -- 400 K) giant exoplanets. We can therefore use their atmospheres as proxies for planetary atmospheres, testing our understanding of…