Related papers: Brown Dwarfs from the Stellar Perspective

We present the results of a deep-imaging search for wide companions to low-mass stars and brown dwarfs using NSFCam on IRTF. We searched a sample of 132 M7-L8 dwarfs to magnitude limits of $J \sim 20.5$ and $K \sim 18.5$, corresponding to…

We have obtained infrared (1 to 2.5 micron) spectroscopy for 42 halo and disk dwarfs with spectral type M1 to M6.5. These data are compared to synthetic spectra generated by the latest model atmospheres of Allard & Hauschildt. Photospheric…

Benchmark brown dwarfs in wide binary systems are crucial for characterizing substellar objects and calibrating atmospheric and evolutionary models. However, brown dwarf benchmarks with subsolar metallicity, very cool temperatures, or…

We present a 20-pc, volume-limited sample of M7-L8 dwarfs created through spectroscopic follow-up of sources selected from the Two Micron All Sky Survey (2MASS) Second Incremental Release Point Source Catalog. In this paper, we present…

Cool subdwarfs of types K and M are the fainter counterparts of cool main sequence dwarfs that dominate the Galactic population. In this paper we present the results of an optical speckle survey of 62 confirmed cool subdwarf systems within…

We present near-infrared spectra for a sample of T dwarfs, including eleven new discoveries made using the Two Micron All Sky Survey. These objects are distinguished from warmer (L-type) brown dwarfs by the presence of methane absorption…

The new spectroscopic classes, L and T, are defined by the role of dust clouds in their atmospheres, the former by their presence and the latter by their removal and near absence. Moreover, the M to L and L to T transitions are intimately…

(abridged) We report the discovery of a very cool brown dwarf, ULAS J003402.77-005206.7 (ULAS J0034-00), identified in UKIDSS DR1. We provide optical, near-infrared, and mid-infrared photometry of the source, and two near-infrared spectra.…

We have obtained a good quality R$\sim$400 0.8-2.5 $\mu$m spectrum and accurate photometry of Gl 570D, one of the coolest and least luminous brown dwarfs currently known. The spectrum shows that Gl 570D has deeper absorptions in the strong…

We have identified CFBDS J1458+10 as a 0.11" (2.6 AU) physical binary using Keck laser guide star adaptive optics imaging and have measured a distance of 23.1+/-2.4 pc to the system based on near-IR parallax data from CFHT. The…

Context. M-type subdwarfs are metal-poor low-mass stars and probe for the old populations in our Galaxy. Accurate knowledge of their atmospheric parameters and especially the composition is essential for understanding the chemical history…

We present a review of the most recent improvements in the theory of low-mass star-like objects, in the stellar and sub-stellar domains. Comparison is made with various recent observations.

In this review, we examine the successes and weaknesses of modern low-mass star and brown dwarf theory.(1) We first focus on the mechanical (equation of state) and thermal (atmosphere) properties and on the evolution. We then examine the…

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…

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)…

To better understand the potential habitability of planets orbiting brown dwarfs, this work presents a new set of equilibrium temperature evolution tracks. Unlike most previous work that relied on analytic scaling relationships for brown…

We have been using Keck laser guide star adaptive optics to monitor the orbits of ultracool binaries, providing dynamical masses at lower luminosities and temperatures than previously available and enabling strong tests of theoretical…

We describe a method for accurately determining M dwarf metallicities with spectral synthesis based on abundance analyses of visual binary stars. We obtained high resolution, high signal-to-noise spectra of each component of five visual…

As brown dwarfs cool, a variety of species condense in their atmospheres, forming clouds. Iron and silicate clouds shape the emergent spectra of L dwarfs, but these clouds dissipate at the L/T transition. A variety of other condensates are…

We present improved atmospheric parameters of nearby white dwarfs lying within 20 pc of the Sun. The aim of the current study is to obtain the best statistical model of the least-biased sample of the white dwarf population. A homogeneous…