Related papers: Clouds, Brightening and Multiplicity Across the L …

We present new 5.2-14.5 micron low-resolution spectra of 14 mid-L to mid-T dwarfs, as well as 3.0-4.1 micron spectra for five of these dwarfs. These data are supplemented by existing red and near-infrared spectra (0.6-2.5 micron), as well…

Brown dwarfs that gain mass through binary interactions may be pushed above the boundary that divides brown dwarfs from low-mass stars: the hydrogen burning limit (HBL). Some of these objects will make their way to the main sequence and may…

In this paper, we calculate new line lists and opacities for the 12 bands of the A$^6\Sigma^{+}$ -- X$^6\Sigma^{+}$ transitions of the CrH molecule. Identified in objects of the new L dwarf spectroscopic class (many of which are brown…

We present photometric light curves for a sample of 21 ultra cool M and L dwarfs in the field and in the young open clusters sigma Orionis and the Pleiades. Evidence for variability with RMS amplitudes (in the I band) of 0.01 to 0.055…

We present a kinematic analysis of 152 low surface gravity M7-L8 dwarfs by adding 8 parallaxes, 38 radial velocities, and 19 proper motions. We find 39 objects to be high-likelihood or bona fide members of nearby moving groups, 92 objects…

I review the optical and near-infrared spectral characteristics of the extremely cool dwarfs grouped under the new classification of type L. These include both very low-mass stars and brown dwarfs, and we discuss the likely temperature…

Binary statistics of the latest-type T and Y brown dwarfs are sparse and it is unclear whether the trends seen in the multiplicity properties of their more massive counterparts hold for the very coolest brown dwarfs. We present results from…

We present a detailed examination of the brown dwarf multiples 2MASS J08503593+1057156 and 2MASS J17281150+3948593, both suspected of harboring components that straddle the L dwarf/T dwarf transition. Resolved photometry from Hubble Space…

We report the discovery of 87 new T dwarfs uncovered with the Wide-field Infrared Survey Explorer (WISE) and three brown dwarfs with extremely red near-infrared colors that exhibit characteristics of both L and T dwarfs. Two of the new T…

We present new high contrast imaging of 8 L/T transition brown dwarfs using the NIRC2 camera on the Keck II telescope. One of our targets, the T3.5 dwarf 2MASS J08381155 + 1511155, was resolved into a hierarchal triple with projected…

We present the discovery of SDSS J042348.57-041403.5 as a closely-separated (0"16) brown dwarf binary, resolved by the Hubble Space Telescope Near Infrared Camera and Multi-Object Spectrometer. Physical association is deduced from the…

Among the greatest challenges in understanding ultra-cool brown dwarf and exoplanet atmospheres is the evolution of cloud structure as a function of temperature and gravity. In this study, we present the rotational modulations of GU Psc b…

We have undertaken a series of hydrodynamic + N-body simulations in order to explore the properties of young stars. Our results suggest that the IMF may be sensitive to environment in its substellar region, with more brown dwarfs being…

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…

We present initial results from a wide-field (30,000 deg^2) search for L/T transition brown dwarfs within 25 pc using the Pan-STARRS1 and WISE surveys. Previous large-area searches have been incomplete for L/T transition dwarfs, because…

We present JHK photometry and spectroscopy for a sample of newly identified L and T dwarfs from the Sloan Digital Sky Survey (SDSS) and known dwarfs from the SDSS and the Two Micron All Sky Survey (2MASS). Spectral classification has been…

The L/T transition is an important evolutionary phase in brown dwarf atmospheres, providing us with a unique opportunity to explore the effects of clouds, convection, winds, gravity and metallicity across a very narrow temperature range.…

We present a sequence of high resolution (R~20,000 or 15 km/s) infrared spectra of stars and brown dwarfs spanning spectral types M2.5 to T6. Observations of 16 objects were obtained using eight echelle orders to cover part of the J-band…

Theoretical aspects of modeling of spectra of late M- and L-dwarfs are discussed. We show, that the processes of formation of spectra of M- and L-dwarfs are basically different. Instead of the case of M-dwarfs, atoms of Ti and V should be…

This chapter reviews our current knowledge of metal-poor ultracool dwarfs with spectral types later than M7. The current census of M, L, and T subdwarfs is explored. The main colour trends of subdwarfs from the optical to the mid-infrared…