ULAS J141623.94+134836.3-a faint common proper motion companion of a nearby L dwarf Serendipitous discovery of a cool brown dwarf in UKIDSS DR6

作者：Scholz R D^*

来源：Astronomy & Astrophysics, 2010, 510: L8.

DOI：10.1051/0004-6361/201014078

• astrometry
• stars: distances
• stars: kinematics and dynamics
• brown dwarfs
• solar neighborhood

Aims. New near-infrared large-area sky surveys (e.g. UKIDSS, CFBDS, WISE) go deeper than 2MASS and aim at detecting brown dwarfs lurking in the solar neighbourhood that are even fainter than the latest known T-type objects, so-called Y dwarfs.
Methods. Using UKIDSS data, we found a faint brown dwarf candidate with very red optical-to-near-infrared, but extremely blue near-infrared colours next to the recently discovered nearby L dwarf SDSS J141624.08+134826.7. We checked if the two objects are co-moving by studying their parallactic and proper motion and compared the new object with known T dwarfs.
Results. The astrometric measurements are consistent with a physical pair (sep approximate to 75 AU) at a distance d approximate to 8 pc. The extreme colour (J - K approximate to -1.7) and absolute magnitude (M-J = 17.78 +/- 0.46 and M-K = 19.45 +/- 0.52) make the new object appear as one of the coolest (T-eff approximate to 600 K) and nearest brown dwarfs, probably of late-T spectral type and possibly with a high surface gravity (log g approximate to 5.0)

• 出版日期2010-2