Discovery of Two Very Wide Binaries with Ultracool Companions and a New Brown Dwarf at the L/T Transition

Mužić, Koraljka; Radigan, Jacqueline; Jayawardhana, Ray; Ivanov, Valentin D.; Faherty, Jacqueline K.; Kurtev, Radostin G.; Núñez, Alejandro; Boffin, Henri M. J.; Hainaut, Olivier; Cruz, Kelle; Jones, David; Metchev, Stanimir; Tyndall, Amy; Borissova, Jura
The Astronomical Journal, Volume 144, Issue 6, article id. 180, 11 pp. (2012).


We present the discovery and spectroscopic follow-up of a nearby late-type L dwarf (2M0614+3950), and two extremely wide very low mass binary systems (2M0525-7425AB and 2M1348-1344AB), resulting from our search for common proper motion pairs containing ultracool components in the Two Micron All Sky Survey and the Wide-field Infrared Survey Explorer catalogs. The near-infrared spectrum of 2M0614+3950 indicates a spectral type L9 ± 1 object residing at a distance of 26.0 ± 1.8 pc. The optical spectrum of 2M0525-7425A reveals an M3.0 ± 0.5 dwarf primary, accompanied by a secondary previously classified as L2. The system has an angular separation of ~44'', equivalent to ~2000 AU at a distance of 46.0 ± 3.0 pc. Using optical and infrared spectra, respectively, we classify the components of 2M1348-1344AB as M4.5 ± 0.5 and T5.5 ± 1. The angular separation of ~68'' is equivalent to ~1400 AU at a distance of 20.7 ± 1.4 pc. 2M1348-1344AB is one of only six very wide (separation >1000 AU) systems containing late T dwarfs known to date.