Related papers: LP 349-25: a new tight M8V binary
We present radio observations of 8 ultracool dwarfs with a narrow spectral type range (M8-M9.5) using the Very Large Array at 8.5 GHz. Only the tight M8 binary LP 349-25 was detected. LP 349-25 is the tenth ultracool dwarf system detected…
LP~349$-$25 is a well studied close stellar binary system comprised of two late M dwarf stars, both stars close to the limit between star and brown dwarf. This system was previously identified as a source of GHz radio emission. We observed…
We report the discovery of companions to 5 nearby late M dwarfs (>M5), LHS1901, LHS4009, LHS6167, LP869-26 and WT460, and we confirm that the recently discovered mid-T brown dwarf companion to SCR1845-6357 is physically bound to that star.…
We have recently identified the widest very low-mass binary (2M0126AB), consisting of an M6.5V and an M8V dwarf with a separation of ~5100 AU, which is twice as large as that of the second widest known system and an order of magnitude…
As part of an ongoing study to determine the distribution of orbital parameters for massive binaries in the Cygnus OB2 Association, we present the orbital solutions for two new single-lined spectroscopic binaries, MT059 (O8V) & MT258 (O8V),…
We present updated results of a high-resolution, magnitude limited (Ks<12 mag) imaging survey of nearby low-mass M6.0-M7.5 field stars. The observations were carried out using adaptive optics at the Gemini North, VLT, Keck II, and Subaru…
A survey of 30 nearby M6.0-M7.5 dwarfs with Ks<12 mag utilizing the Hokupa'a adaptive optics system at the Gemini North Telescope has discovered 3 new binary systems. All 3 systems have separations between 0.12-0.29 arcsec (3-10 AU) with…
We have discovered a new, near-equal mass, eclipsing M dwarf binary from the Next Generation Transit Survey. This system is only one of 3 field age ($>$ 1 Gyr), late M dwarf eclipsing binaries known, and has a period of 1.74774 days,…
Use of the highly sensitive Hokupa'a/Gemini curvature wavefront sensor has allowed for the first time direct adaptive optics (AO) guiding on M8-M9 very low mass (VLM) stars. An initial survey of 20 such objects (SpT=M8-M9) discovered 4…
Context: Most stars in the galactic stellar population are low-mass stars. Very low-mass (VLM) stars are a subset of the low-mass stars typically defined in terms of the stellar masses ranging from 0.6 M_sun to the hydrogen-burning limit of…
We report the discovery of a very low mass binary system (primary mass <0.1 Msol) with a projected separation of ~5100 AU, more than twice that of the widest previously known system. A spectrum covering the 1-2.5 microns wavelength interval…
We report the discovery of a faint L6 \pm 1 companion to the previously known M9 dwarf, 2MASS J01303563-4445411, based on our near-infrared imaging and spectroscopic observations with the 3m Infrared Telescope Facility SpeX…
We present results from a high-angular-resolution survey of 78 very low mass (VLM) binary systems with 6.0 <= V-K colour <= 7.5 and proper motion >= 0.15 arcsec/yr. 21 VLM binaries were detected, 13 of them new discoveries. The new binary…
We present the discovery of 2MASS J21321145+1341584AB as a closely separated (0.066") very low-mass field dwarf binary resolved in the near-infrared by the Keck II Telescope using laser guide star adaptive optics. Physical association is…
We survey a sample of 32 M5-M8 stars with distance < 40pc for companions with separations between 0.1 arcsec and 1.5 arcsec and with Delta m_i <5. We find five new VLM binaries with separations between 0.15 arcsec and 1.1 arcsec, including…
We present optical photometry of the low mass X-ray binary systems GX 349+2 and Ser X-1. Extensive VRI photometry of the faint optical counterpart (V=18.4) to GX 349+2 reveals a period of 22.5 +/- 0.1 h and half-amplitude 0.2 mag. This…
Tightest known quadruple systems VW LMi consists of contact eclipsing binary with P_12 = 0.477551 days and detached binary with P_34 = 7.93063 days revolving in rather tight, 355.0-days orbit. This paper presents new photometric and…
We used very long baseline interferometry to constrain the orbit of the binary system 2MASS J05082729-2101444. We observed the system with the VLBA in three epochs at a frequency of 4.85 GHz, which provides an angular resolution of about 3…
Use of the highly sensitive Hokupa'a/Gemini curvature wavefront sensor has allowed direct adaptive optics (AO) guiding on very low mass (VLM) stars with SpT=M8.0-L0.5. A survey of 39 such objects detected 9 VLM binaries. Most of these…
LMC P3 is the most luminous gamma-ray binary discovered to date and the first detected outside of the Galaxy, with an orbital period of 10.301 d. We report on optical spectroscopic observations undertaken with the Southern African Large…