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| Paper: |
A Very Cool, Very Nearby Brown Dwarf Hiding in the Galactic Plane |
| Volume: |
448, 16th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun |
| Page: |
339 |
| Authors: |
Lucas, P. W.; Tinney, C. G.; Burningham, B.; Leggett, S. K.; Pinfield, D. J.; Smart, R.; Jones, H. R. A.; Marocco, F.; Barber, R. J.; Yurchenko, S. N.; Tennyson, J.; Ishii, M.; Tamura, M.; Day-Jones, A. C.; Adamson, A.; Allard, F.; Homeier, D. |
| Abstract: |
The UKIDSS Galactic Plane Survey (GPS) has provided near infrared data on several hundred
million sources, most of which is now world public.
We report the discovery of a very cool, isolated brown dwarf, UGPS 0722-05, which was identified as
the sole candidate late T dwarf in the 6th Data Release via a simple SQL query, followed by inspection
of a handful of images.
The near-infrared spectrum UGPS 0722-05 displays deeper H2O
and CH4 troughs than the coolest T dwarfs previously known, so we provisionally classify
it as a T10 dwarf. The distance is measured by trigonometric parallax as d=4.1–0.5+0.6 pc,
making it the closest known isolated brown dwarf. With the aid of Spitzer/IRAC we measure
H-[4.5] = 4.71, which is redder than all previously known T dwarfs except the peculiar T7.5 dwarf
SDSS J1416+13B, which is thought to be warmer and more luminous than UGPS 0722-05.
We estimate that UGPS 0722-05 has Teff=520±40 K. We place this discovery in the context
of other recent discoveries from the UKIDSS Large Area Survey and note that there appears to
be a deficit of late T dwarfs in the local field relative to predictions based on the IMF
measured in young clusters. We comment on possible explanations for this. |
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