Related papers: The discovery of an M4+T8.5 binary system

In near-infrared NaCo observations of the young brown dwarf 2MASS J0041353-562112, we discovered a companion a little less than a magnitude fainter than the primary. The binary candidate has a separation of 143 mas, the spectral types are…

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…

We report resolved near-infrared spectroscopy and photometry of the recently identified brown dwarf binary WISE J104915.57-531906.1AB, located 2.02+/-0.15 pc from the Sun. Low-resolution spectral data from Magellan/FIRE and IRTF/SpeX reveal…

Context. Being the most numerous and oldest stars in the galaxy, M dwarfs are objects of great interest for exoplanet searches. The presence of molecules in their atmosphere complicates our understanding of their atmospheric properties. But…

We identify a sample of near-equal mass wide binary M dwarf systems from the SLoWPoKES catalog of common proper-motion binaries and obtain follow-up observations of their chromospheric activity as measured by the H$\alpha$ emission line. We…

We investigate the relationship between age and chromospheric activity for 139 M dwarf stars in wide binary systems with white dwarf companions. The age of each system is determined from the cooling age of its white dwarf component. The…

We present spatially resolved photometric and spectroscopic observations of two wide brown dwarf binaries uncovered by the SIMP near-infrared proper motion survey. The first pair (SIMP J1619275+031350AB) has a separation of 0.691" (15.2 AU)…

We present the discovery of five late-type T dwarfs identified with the Wide-field Infrared Survey Explorer (WISE). Low-resolution near-infrared spectroscopy obtained with the Magellan Folded-port InfraRed Echellette (FIRE) reveal strong…

We present the discovery of 11 new T dwarfs, found during the course of a photometric survey for mid-to-late T dwarfs in the 2MASS Point Source Catalog and from a proper motion selected sample of ultracool dwarfs in the 2MASS Working…

In this work, we calibrate the relationship between Halpha emission and M dwarf ages. We compile a sample of 892 M dwarfs with Halpha equivalent width (HaEW) measurements from the literature that are either co-moving with a white dwarf of…

We have revisited the sdB+K-star long-period binary PG 1018-047 based on 20 new high-resolution VLT/UVES spectra that provided regular coverage over a period of more than 26 months. We refine the period and establish that the orbit is…

We present moderate-resolution ($R$$\sim$4000-5000) near-infrared integral field spectroscopy of the young (1-5 Myr) 6-14 $M_\mathrm{Jup}$ companions ROXs 42B b and FW Tau b obtained with Keck/OSIRIS and Gemini-North/NIFS. The spectrum of…

[Abridged] We present the first simultaneous radio, X-ray, ultraviolet, and optical spectroscopic observations of the M8.5 dwarf TVLM513-46546, with a duration of 9 hours. These observations are part of a program to study the origin of…

We have discovered that the brown dwarf WISEJ014656.66+423410.0 is a close binary (0.0875$\pm$0.0021 arcsec, 0.93$^{+0.12}_{-0.16}$ AU) from Keck laser guide star adaptive optics imaging. Our photometry for this system reveals that both…

Using WFPC2 on the Hubble Space Telescope, we have isolated a sample of 258 white dwarfs (WDs) in the Galactic globular cluster M4. Fields at three radial distances from the cluster center were observed and sizeable WD populations were…

We report the detections of low-mass companions to five M and L dwarfs within 10 pc of the Sun using the Hubble Space Telescope (HST) Near-Infrared Camera and Multi-Object Spectrometer (NICMOS). Follow-up observations using the HST Advanced…

Using Keck laser guide star adaptive optics imaging, we have found that the T9 dwarf WISE J1217+1626 and T8 dwarf WISE J1711+3500 are exceptional binaries, with unusually wide separations (~0.8 arcsec, 8-15 AU), large near-IR flux ratios…

We present new Spitzer IRAC/PU/MIPS photometry from 3.6 to 24 um, and new Gemini GMOS photometry at 0.48 um, of the young brown dwarf eclipsing binary 2MASS J05352184-0546085, located in the Orion Nebula Cluster. No excess disk emission is…

We present two confirmed wide separation L-dwarf common proper motion companions to nearby stars and one candidate identified from the Two Micron All Sky Survey. Spectral types from optical spectroscopy are L0 V, L2.5 V, and L8 V.…

We report the discovery of a bright (V ~ 13.7), extremely low-mass white dwarf in a close double degenerate system. We originally selected GALEX J171708.5+675712 for spectroscopic follow-up among a group of white dwarf candidates in an…