Related papers: Five new very low mass binaries
As part of our search for young M dwarfs within 25 pc, we acquired high-resolution spectra of 185 low-mass stars compiled by the NStars project that have strong X-ray emission. By cross-correlating these spectra with radial velocity…
The project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (MUCHFUSS) aims at finding hot subdwarf stars with massive compact companions like massive white dwarfs (M>1.0 M$_\odot$), neutron stars, or stellar-mass black…
LP~349$-$25 is a well studied close stellar binary system comprised of two late M dwarf stars, both stars close to the limit between star and brown dwarf. This system was previously identified as a source of GHz radio emission. We observed…
Searches for companions of brown dwarfs by direct imaging mainly probe orbital separations > 3-10 AU. On the other hand, previous radial velocity surveys of brown dwarfs are mainly sensitive to separations smaller than 0.6 AU. It has been…
I report the results of a survey for low-mass (0.030 <~ M <~ 0.013 M_solar) brown dwarfs in the direction of the TW Hya association using 2MASS. Two late-M dwarfs show signs of low surface gravity and are strong candidates to be young,…
We have obtained HST Planetary Camera observations of a total of fifty-three low-mass (M < 0.3 M_solar) members of the Hyades cluster. Nine of these stars are resolved as binaries, with separations between 0.1 and 3.1 arcseconds, while a…
A survey of 30 nearby M6.0-M7.5 dwarfs with Ks<12 mag utilizing the Hokupa'a adaptive optics system at the Gemini North Telescope has discovered 3 new binary systems. All 3 systems have separations between 0.12-0.29 arcsec (3-10 AU) with…
We report the discovery of a brown dwarf companion to the young M dwarf 1RXS J235133.3+312720 as part of a high contrast imaging search for planets around nearby young low-mass stars with Keck-II/NIRC2 and Subaru/HiCIAO. The 2.4" (~120 AU)…
Benchmark brown dwarfs are those objects for which fiducial constraints are available, including effective temperature, parallax, age, metallicity. We searched for new cool brown dwarfs in 186 sq.deg. of the new area covered by the data…
We search for stellar and substellar companions of young nearby stars to investigate stellar multiplicity and formation of stellar and substellar companions. We detect common proper-motion companions of stars via multi-epoch imaging. Their…
We present high time resolution SDSS-$g'$ and SDSS-$z'$ light curves of the primary eclipse in SDSS J141126.20+200911.1, together with time-resolved X-Shooter spectroscopy and near-infrared $JHK_{s}$ photometry. Our observations confirm the…
The project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (MUCHFUSS) aims at finding hot subdwarf stars (sdBs) with massive compact companions such as white dwarfs, neutron stars, or stellar-mass black holes. In a…
Only a few well characterized very low-mass M dwarfs are known today. Our understanding of M dwarfs is vital as these are the most common stars in our solar neighborhood. We aim to characterize the properties of a rare F+dM stellar system…
Evidence is presented that 2MASS J03202839-0446358, a late-type dwarf with discrepant optical (M8:) and near-infrared (L1) spectral types, is an as-yet unresolved stellar/brown dwarf binary with late-type M dwarf and T dwarf components.…
Astrometric observations of resolved binaries provide estimates of orbital periods and will eventually lead to measurement of dynamical masses. Only a few very low mass star and brown dwarf masses have been measured to date, and the…
We report the detection of seven low mass companions to intermediate-mass stars (SpT B/A/F; $M$$\approx$1.5-4.5 solar masses) in the Scorpius-Centaurus Association using nonredundant aperture masking interferometry. Our newly detected…
The magnetic white dwarf SDSS J121209.31+013627.7 exhibits a weak, narrow Halpha emission line whose radial velocity and strength are modulated on a period of ~90 minutes. Though indicative of irradiation on a nearby companion, no cool…
We present VLT/NACO SDI images of the very nearby star SCR 1845-6357 (hereafter SCR 1845). SCR 1845 is a recently discovered (Hambly et al. 2004) M8.5 star just 3.85 pc from the sun (Henry et al. 2006). Using the capabilities of the unique…
We have spectroscopically confirmed a brown dwarf mass companion to the hydrogen atmosphere white dwarf NLTT5306. The white dwarf's atmospheric parameters were measured using Sloan Digital Sky Survey and X-Shooter spectroscopy as…
We report the discovery of a substellar companion to 2MASS J02192210-3925225, a young M6 $\gamma$ candidate member of the Tucana-Horologium association (30 - 40 Myr). This L4 $\gamma$ companion has been discovered with seeing-limited direct…