The discovery of a very cool, very nearby brown dwarf in the Galactic plane
We report the discovery of a very cool, isolated brown dwarf, UGPS 0722−05, with the United Kingdom Infrared Telescope Deep Sky Survey (UKIDSS) Galactic Plane Survey. The near-infrared spectrum displays deeper H2O and CH4 troughs than the coolest known T dwarfs and an unidentified absorption feature at 1.275 μm. We provisionally classify the object as a T10 dwarf but note that it may in future come to be regarded as the first example of a new spectral type. The distance is measured by trigonometric parallax as d= 4.1+0.6−0.5 pc, making it the closest known isolated brown dwarf. With the aid of Spitzer/Infrared Array Camera (IRAC) we measure H−[4.5]= 4.71. It is the coolest brown dwarf presently known – the only known T dwarf that is redder in H−[4.5] is the peculiar T7.5 dwarf SDSS J1416+13B, which is thought to be warmer and more luminous than UGPS 0722−05. Our measurement of the luminosity, aided by Gemini/T-ReCS N-band photometry, is L= 9.2 ± 3.1 × 10−7 L⊙. Using a comparison with well-studied T8.5 and T9 dwarfs we deduce Teff= 520 ± 40 K. This is supported by predictions of the Saumon & Marley models. With apparent magnitude J= 16.52, UGPS 0722−05 is the brightest of the ∼90 T dwarfs discovered by UKIDSS so far. It offers opportunities for future study via high-resolution near-infrared spectroscopy and spectroscopy in the thermal infrared.
Item Type | Article |
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Uncontrolled Keywords | surveys; brown dwarfs; stars: low mass; INITIAL MASS FUNCTION; METHANE T-DWARFS; SKY SURVEY; SOLAR NEIGHBORHOOD; UKIDSS; COMPANION; PARALLAXES; AGE |
Date Deposited | 26 Jul 2024 11:04 |
Last Modified | 26 Jul 2024 11:04 |
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Read more research from the creator(s):
- Lucas, P.W.
- Tinney, C. G.
- Burningham, B.
- Leggett, S. K.
- Pinfield, D.J.
- Smart, Richard
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- Marocco, F.
- Barber, Robert J.
- Yurchenko, Sergei N.
- Tennyson, Jonathan
- Ishii, Miki
- Tamura, Motohide
- Day-Jones, Avril C.
- Adamson, Andrew
- Allard, France
- Homeier, Derek
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