The discovery of the T8.5 dwarf UGPS J0521+3640

Burningham, Ben; Lucas, P. W.; Leggett, S. K.; Smart, R.; Baker, D.; Pinfield, D. J.; Tinney, C. G.; Homeier, D.; Allard, F.; Zhang, Z. H.; Gomes, J.; Day-Jones, A. C.; Jones, H. R. A.; Kovács, G.; Lodieu, N.; Marocco, F.; Murray, D. N.; Sipőcz, B.
Referencia bibliográfica

Monthly Notices of the Royal Astronomical Society: Letters, Volume 414, Issue 1, pp. L90-L94.

Fecha de publicación:
6
2011
Número de autores
18
Número de autores del IAC
1
Número de citas
23
Número de citas referidas
22
Descripción
We have carried out a search for late-type T dwarfs in the UKIRT Infrared Deep Sky Survey Galactic Plane Survey 6th Data Release. The search yielded two persuasive candidates, both of which have been confirmed as T dwarfs. The brightest, UGPS J0521+3640, has been assigned the spectral type T8.5 and appears to lie at a distance of 7-9 pc. The fainter of the two, UGPS J0652+0324, is classified as a T5.5 dwarf and lies at an estimated distance of 28-37 pc. Warm-Spitzer observations in IRAC channels 1 and 2, taken as part of the GLIMPSE360 Legacy Survey, are available for UGPS J0521+3640 and we used these data with the near-infrared spectroscopy to estimate its properties. We find best-fitting solar metallicity BT-Settl models for Teff= 600 and 650 K and log g= 4.5 and 5.0. These parameters suggest a mass between 14 and 32MJ for an age between 1 and 5 Gyr. The proximity of this very cool T dwarf, and its location in the Galactic plane, makes it an ideal candidate for high-resolution adaptive optics imaging to search for cool companions.