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
Abstract
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 ≈75 AU) at a distance d ≈ 8 pc. The extreme colour (J-K≈-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≈ 600 K) and nearest brown dwarfs, probably of late-T spectral type and possibly with a high surface gravity (log g≈ 5.0).
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 2010
- DOI:
- 10.1051/0004-6361/201014078
- arXiv:
- arXiv:1001.2743
- Bibcode:
- 2010A&A...510L...8S
- Keywords:
-
- astrometry;
- stars: distances;
- stars: kinematics and dynamics;
- brown dwarfs;
- solar neighborhood;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- accepted for publication as a Letter in Astronomy and Astrophysics, 4 pages, 7 figures, changed subtitle and discussion, former Fig. 4 removed, new Figs. 2, 6, and 7