Related papers: Dynamical masses for the nearest brown dwarf binar…

Although many models have been proposed, the physical mechanisms responsible for the formation of low-mass brown dwarfs are poorly understood. The multiplicity properties and minimum mass of the brown-dwarf mass function provide critical…

The binary nature of the M8.5 dwarf DENIS J063001.4$-$184014AB (DE0630$-$18) was discovered with astrometric monitoring from the ground, which determined the unresolved photocentric orbit and the trigonometric parallax of the system. Here…

The study of high contrast imaged brown dwarfs and exoplanets depends strongly on evolutionary models. To estimate the mass of a directly imaged substellar object, its extracted photometry or spectrum is used and adjusted with model spectra…

We report the discovery of the first brown dwarf binary system with a Y dwarf primary, WISE J033605.05$-$014350.4, observed with NIRCam on JWST with the F150W and F480M filters. We employed an empirical point spread function binary model to…

WISE J104915.57$-$531906.1 is a L/T brown dwarf binary located 2pc from the Sun. The pair contains the closest known brown dwarfs and is the third closest known system, stellar or sub-stellar. We report comprehensive follow-up observations…

Neuhaeuser & Comeron (1998, 1999) presented direct imaging evidence, as well as first spectra, of several young stellar and sub-stellar M6- to M8-type objects in the Cha I dark cloud. One of these objects is Cha Halpha 2, classified as…

With more adaptive optics images available, we aim at detecting orbital motion for the first time in the system TWA 5 A+B. We measured separation and position angle between TWA 5 A and B in each high-resolution image available and followed…

Using astrometric measurements obtained with the FORS2/VLT camera, we are searching for low-mass companions around 20 nearby ultracool dwarfs. With a single-measurement precision of 0.1 milli-arcseconds, our survey is sensitive to a wide…

The formation mechanism of brown dwarfs (BDs) is one of the long-standing problems in star formation because the typical Jeans mass in molecular clouds is too large to form these substellar objects. To answer this question, it is crucial to…

We present HST/WFPC2 observations of a sample of 134 ultra-cool objects (spectral types later than M7) coming from the DENIS, 2MASS and SDSS surveys, with distances estimated to range from 7 pc to 105 pc. Fifteen new ultra-cool binary…

We report the discovery of 14 low-mass binary systems containing mid-M to mid-L dwarf companions with separations larger than 250 AU. We also report the independent discovery of 9 other systems with similar characteristics that were…

The nearby late M star Gliese 569B was recently found by adaptive optics imaging to be a double with separation ~1 AU. To explore the orbital motion and masses, we have undertaken a high resolution (~0.05 arcsec) astrometric study. Images…

We analyse FORS2/VLT $I$-band imaging data to monitor the motions of both components in the nearest known binary brown dwarf WISE J104915.57-531906.1AB (LUH16) over one year. The astrometry is dominated by parallax and proper motion, but…

Aims. Measuring dynamical masses of substellar companions is a powerful tool to test models of mass-luminosity-age relations, as well as determining observational features that constrain the boundary between stellar and substellar…

We present the results of a high-resolution imaging survey of 12 brown dwarfs and very low mass stars in the closest (~145 pc) young (~5 Myr) OB association, Upper Scorpius. We obtained images with the Advanced Camera for Surveys/High…

Epsilon Indi A b is a directly imaged $\sim6 M_{\rm Jup}$ exoplanet orbiting a nearby (3.6 pc) K-dwarf at $\sim 30$ AU. We analyze archival JWST/MIRI 15 $\mu$m coronagraphic imaging of this planet to search for directly imaged satellites…

I present observations of a new faint double, 2MASS J11011926-7732383AB, toward the Chamaeleon I star-forming region. From optical and near-infrared images of the pair, I measure a separation of 1.44" and extract RIJHK_s photometry of the…

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…

Although many new brown dwarf (BD) neighbours have recently been discovered thanks to new sky surveys in the mid- and near-infrared (MIR, NIR), their numbers are still more than five times lower than those of stars in the same volume. Our…

(Abridged) We present multi-epoch imaging of the T5.0+T5.5 binary 2MASS J1534-2952AB obtained with the Keck laser guide star adaptive optics system. Combined with an extensive (re-)analysis of archival HST imaging, we find a total mass of…