2010/04/30 by Philip W. Lucas, P. W. Lucas, C. G. Tinney +16 · 1 citation
Physics and Astronomy · Social Sciences · #Absolute magnitude #Astronomy and Astrophysical Research #Brown dwarf #Dwarf galaxy #Educational Leadership and Practices #Galactic plane #James Webb Space Telescope #Parallax #Proper motion #Sky #Spectroscopy #Stellar, planetary, and galactic studies #astro-ph.EP #astro-ph.IM #astro-ph.SR
paper · pdf · doi:10.1111/j.1745-3933.2010.00927.x
Accepted by MNRAS Letters. Note that preliminary parallax measurement changed significantly after version 1 so the paper was withdrawn from Nature
arxiv created 2010/08/12 · openalex publication_date 2010/08/29 · arxiv updated 2015/05/18 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Abstract 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.