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Eight new T4.5–T7.5 dwarfs discovered in the UKIDSS Large Area Survey Data Release 1

journal contribution
posted on 2023-05-17, 14:33 authored by Lodieu, N, Pinfield, DJ, Legget, SK, Jameson, RF, Mortlock, DJ, Warren, SJ, Burningham, B, Lucas, PW, Chiu, K, Liu, MC, Venemans, BP, McMahon, RG, Allard, F, Baraffe, I, Barrado y Navacues, D, Carraro, G, Casewell, SL, Chabrier, G, Chappelle, RJ, Clarke, F, Day-Jones, AC, Deacon, NR, Dobbie, PD, Folkes, SL, Hambly, NC, Hewett, PC, Hodgkin, ST, Jones, HRA, Kendall, TR, Magazzu, A, Martin, EL, McCaughrean, MJ, Nakajima, T, Pavlenko, Y, Tamura, M, Tinney, CG, Zapatero Osorio, MR
We present eight new T4.5–T7.5 dwarfs identified in the UKIRT (United Kingdom Infrared Telescope) Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) Data Release 1 (DR1). In addition we have recovered the T4.5 dwarf SDSS J020742.91+000056.2 and the T8.5 dwarf ULAS J003402.77−005206.7. Photometric candidates were picked up in two-colour diagrams over 190 deg2 (DR1) and selected in at least two filters. All candidates exhibit near-infrared spectra with strong methane and water absorption bands characteristic of T dwarfs and the derived spectral types follow the unified scheme of Burgasser et al.. We have found six new T4.5–T5.5 dwarfs, one T7 dwarf, one T7.5 dwarf and recovered a T4.5 dwarf and a T8.5 dwarf. We provide distance estimates which lie in the 15–85 pc range; the T7.5 and T8.5 dwarfs are probably within 25 pc of the Sun. We conclude with a discussion of the number of T dwarfs expected after completion of the LAS, comparing these initial results to theoretical simulations.


Publication title

Monthly Notices of the Royal Astronomical Society










School of Natural Sciences


Blackwell Publishing Ltd

Place of publication

9600 Garsington Rd, Oxford, England, Oxon, Ox4 2Dg

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Copyright 2007 The Authors. Journal compilation copyright? 2007 RAS

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