Related papers: Keck Imaging of Binary L Dwarfs

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 CWISE J151044.74$-$524923.5, a wide low-mass companion to the nearby ($\sim$24.7 pc) system L 262-74, which was identified through the Backyard Worlds: Planet 9 citizen science project. We detail the properties…

Optical linear polarimetry of 8 ultra cool field dwarfs, with spectral types ranging from M9 to L8, is presented. The linear polarisation, P, of each dwarf we measured is P < 0.2%. Three dwarfs have polarisations compatible with zero, two…

We present the discovery of 34 comoving systems containing an ultra-cool dwarf found by means of the NOIRLab Source Catalog (NSC) DR2. NSC's angular resolution of $\sim$1" allows for the detection of small separation binaries with…

We report the identification of 2MASS J15500845+1455180 as a 0"9 L dwarf visual binary. This source is resolved in Sloan Digital Sky Survey (SDSS) images and in near-infrared imaging with the IRTF SpeX imager/spectrometer. The two…

While stars are often found in binary systems, brown dwarf binaries are much rarer. Brown dwarf--brown dwarf pairs are typically difficult to resolve because they often have very small separations. Using brown dwarfs discovered with data…

LSPM J0651+1843 and LSPM J0651+1845 are two high-proper-motion stars recently claimed to form a binary system, FMR 83, by Rica (2012). Here we characterize the system in detail, using astrometric and photometric data, and find that the pair…

We present the first high-angular resolution survey for multiple systems among very low-mass stars and brown dwarfs in the Hyades open cluster. Using the Keck\,II adaptive optics system, we observed a complete sample of 16 objects with…

We report new spectroscopic results, obtained with UKIRT/CGS4, of a sample of 14 candidate ultracool dwarfs selected from the DENIS (Deep Near-Infrared Survey of the Southern Sky) database. A further object, selected from the 2MASS Second…

We present the results of an intense photometric monitoring in the near-infrared (~0.9 microns) with the TRAPPIST robotic telescope of the newly discovered binary brown dwarf WISE J104915.57-531906.1, the third closest system to the Sun at…

Despite their key role in astrophysics, the binary properties of RR Lyrae stars (RRL) remain almost completely unknown since only a single RRL is confirmed as belonging to a binary system. Finding companions to RRL is difficult since most…

We present near-infrared magnitudes for all white dwarfs (selected from the catalog of McCook & Sion) contained in the 2 Micron All Sky Survey Second Incremental Data Release(2MASS 2IDR). We show that the near-IR color-color diagram is an…

We present the results of a program to acquire photometry for eighty-six late-M, L, and T dwarfs using the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. We examine the behavior of these cool dwarfs in various color-color and…

Double white dwarf (DWD) binaries are expected to be very common in the Milky Way, but their intrinsic faintness challenges the detection of these systems. Currently, only a few tens of detached DWDs are know. Such systems offer the best…

Approximately 70 percent of the nearby white dwarfs appear to be single stars, with the remainder being members of binary or multiple star systems. The most numerous and most easily identifiable systems are those in which the main sequence…

We present results of a high-resolution, near-infrared survey of 41 nearby, young (<~300 Myr) M0-M5.0 dwarfs using the Altair natural guide star adaptive optics system at the Gemini North telescope. Twelve of the objects appear to be…

Searches for companions of brown dwarfs by direct imaging mainly probe orbital separations > 3-10 AU. On the other hand, previous radial velocity surveys of brown dwarfs are mainly sensitive to separations smaller than 0.6 AU. It has been…

We present the first results from our high-precision infrared (IR) astrometry program at the Canada-France-Hawaii Telescope. We measure parallaxes for 83 ultracool dwarfs (spectral types M6--T9) in 49 systems, with a median uncertainty of…

About a third of the hot subdwarfs of spectral type B, which are mostly core-helium burning objects on the extreme horizontal branch, are found in close binaries with cool, low-mass stellar, substellar, or white dwarf companions. They can…

Cool subdwarfs are the oldest members of the low mass stellar population. Mostly present in the galactic halo, subdwarfs are characterized by their low metallicity. Measuring their binary fraction and comparing it to solar metallicity stars…