76 T dwarfs from the UKIDSS LAS: Benchmarks, kinematics and an updated space density

Ben Burningham; C. V. Cardoso; L. Smith; S. K. Leggett; R. L. Smart; A. W. Mann; S. Dhital; P. W. Lucas; C. G. Tinney; D. J. Pinfield; Z. Zhang; C. Morley; D. Saumon; K. Aller; S. P. Littlefair; D. Homeier; N. Lodieu; N. Deacon; M. S. Marley; L. van Spaandonk; D. Baker; F. Allard; A. H. Andrei; J. Canty; J. Clarke; A. C. Day-Jones; T. Dupuy; J. J. Fortney; J. Gomes; M. Ishii; H. R.A. Jones; M. Liu; A. Magazzú; F. Marocco; D. N. Murray; B. Rojas-Ayala; M. Tamura

doi:10.1093/mnras/stt740

76 T dwarfs from the UKIDSS LAS: Benchmarks, kinematics and an updated space density

Ben Burningham, C. V. Cardoso, L. Smith, S. K. Leggett, R. L. Smart, A. W. Mann, S. Dhital, P. W. Lucas, C. G. Tinney, D. J. Pinfield, Z. Zhang, C. Morley, D. Saumon, K. Aller, S. P. Littlefair, D. Homeier, N. Lodieu, N. Deacon, M. S. Marley, L. van SpaandonkD. Baker, F. Allard, A. H. Andrei, J. Canty, J. Clarke, A. C. Day-Jones, T. Dupuy, J. J. Fortney, J. Gomes, M. Ishii, H. R.A. Jones, M. Liu, A. Magazzú, F. Marocco, D. N. Murray, B. Rojas-Ayala, M. Tamura

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Abstract

We report the discovery of 76 new T dwarfs from the UKIRT Infrared Deep Sky Survey(UKIDSS) Large Area Survey (LAS). Near-infrared broad-and narrow-band photometry and spectroscopy are presented for the new objects, along withWide-field Infrared Survey Explorer (WISE) andwarm-Spitzer photometry. Proper motions for 128 UKIDSS T dwarfs are presented from a new two epoch LAS proper motion catalogue. We use these motions to identify two new benchmark systems: LHS 6176AB, a T8p+M4 pair and HD 118865AB, a T5.5+F8 pair. Using age constraints from the primaries and evolutionary models to constrain the radii, we have estimated their physical properties from their bolometric luminosity. We compare the colours and properties of known benchmark T dwarfs to the latest model atmospheres and draw two principal conclusions. First, it appears that the H - [4.5] and J - W2 colours are more sensitive to metallicity than has previously been recognized, such that differences in metallicity may dominate over differences in Teffwhen considering relative properties of cool objects using these colours. Secondly, the previously noted apparent dominance of young objects in the late-T dwarf sample is no longer apparent when using the new model grids and the expanded sample of late-T dwarfs and benchmarks. This is supported by the apparently similar distribution of late-T dwarfs and earlier type T dwarfs on reduced proper motion diagrams that we present. Finally, we present updated space densities for the late-T dwarfs, and compare our values to simulation predictions and those from WISE.

Original language	English (US)
Pages (from-to)	457-497
Number of pages	41
Journal	Monthly Notices of the Royal Astronomical Society
Volume	433
Issue number	1
DOIs	https://doi.org/10.1093/mnras/stt740
State	Published - Jul 2013
Externally published	Yes

Keywords

Stars: low-mass
Surveys-brown dwarfs

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1093/mnras/stt740

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Burningham, B., Cardoso, C. V., Smith, L., Leggett, S. K., Smart, R. L., Mann, A. W., Dhital, S., Lucas, P. W., Tinney, C. G., Pinfield, D. J., Zhang, Z., Morley, C., Saumon, D., Aller, K., Littlefair, S. P., Homeier, D., Lodieu, N., Deacon, N., Marley, M. S., ... Tamura, M. (2013). 76 T dwarfs from the UKIDSS LAS: Benchmarks, kinematics and an updated space density. Monthly Notices of the Royal Astronomical Society, 433(1), 457-497. https://doi.org/10.1093/mnras/stt740

Burningham, B, Cardoso, CV, Smith, L, Leggett, SK, Smart, RL, Mann, AW, Dhital, S, Lucas, PW, Tinney, CG, Pinfield, DJ, Zhang, Z, Morley, C, Saumon, D, Aller, K, Littlefair, SP, Homeier, D, Lodieu, N, Deacon, N, Marley, MS, van Spaandonk, L, Baker, D, Allard, F, Andrei, AH, Canty, J, Clarke, J, Day-Jones, AC, Dupuy, T, Fortney, JJ, Gomes, J, Ishii, M, Jones, HRA, Liu, M, Magazzú, A, Marocco, F, Murray, DN, Rojas-Ayala, B & Tamura, M 2013, '76 T dwarfs from the UKIDSS LAS: Benchmarks, kinematics and an updated space density', Monthly Notices of the Royal Astronomical Society, vol. 433, no. 1, pp. 457-497. https://doi.org/10.1093/mnras/stt740

@article{46101cc3af1640d2b235836f21b296b2,

title = "76 T dwarfs from the UKIDSS LAS: Benchmarks, kinematics and an updated space density",

abstract = "We report the discovery of 76 new T dwarfs from the UKIRT Infrared Deep Sky Survey(UKIDSS) Large Area Survey (LAS). Near-infrared broad-and narrow-band photometry and spectroscopy are presented for the new objects, along withWide-field Infrared Survey Explorer (WISE) andwarm-Spitzer photometry. Proper motions for 128 UKIDSS T dwarfs are presented from a new two epoch LAS proper motion catalogue. We use these motions to identify two new benchmark systems: LHS 6176AB, a T8p+M4 pair and HD 118865AB, a T5.5+F8 pair. Using age constraints from the primaries and evolutionary models to constrain the radii, we have estimated their physical properties from their bolometric luminosity. We compare the colours and properties of known benchmark T dwarfs to the latest model atmospheres and draw two principal conclusions. First, it appears that the H - [4.5] and J - W2 colours are more sensitive to metallicity than has previously been recognized, such that differences in metallicity may dominate over differences in Teffwhen considering relative properties of cool objects using these colours. Secondly, the previously noted apparent dominance of young objects in the late-T dwarf sample is no longer apparent when using the new model grids and the expanded sample of late-T dwarfs and benchmarks. This is supported by the apparently similar distribution of late-T dwarfs and earlier type T dwarfs on reduced proper motion diagrams that we present. Finally, we present updated space densities for the late-T dwarfs, and compare our values to simulation predictions and those from WISE.",

keywords = "Stars: low-mass, Surveys-brown dwarfs",

author = "Ben Burningham and Cardoso, {C. V.} and L. Smith and Leggett, {S. K.} and Smart, {R. L.} and Mann, {A. W.} and S. Dhital and Lucas, {P. W.} and Tinney, {C. G.} and Pinfield, {D. J.} and Z. Zhang and C. Morley and D. Saumon and K. Aller and Littlefair, {S. P.} and D. Homeier and N. Lodieu and N. Deacon and Marley, {M. S.} and {van Spaandonk}, L. and D. Baker and F. Allard and Andrei, {A. H.} and J. Canty and J. Clarke and Day-Jones, {A. C.} and T. Dupuy and Fortney, {J. J.} and J. Gomes and M. Ishii and Jones, {H. R.A.} and M. Liu and A. Magazz{\'u} and F. Marocco and Murray, {D. N.} and B. Rojas-Ayala and M. Tamura",

year = "2013",

month = jul,

doi = "10.1093/mnras/stt740",

language = "English (US)",

volume = "433",

pages = "457--497",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "0035-8711",

publisher = "Oxford University Press",

number = "1",

}

TY - JOUR

T1 - 76 T dwarfs from the UKIDSS LAS

T2 - Benchmarks, kinematics and an updated space density

AU - Burningham, Ben

AU - Cardoso, C. V.

AU - Smith, L.

AU - Leggett, S. K.

AU - Smart, R. L.

AU - Mann, A. W.

AU - Dhital, S.

AU - Lucas, P. W.

AU - Tinney, C. G.

AU - Pinfield, D. J.

AU - Zhang, Z.

AU - Morley, C.

AU - Saumon, D.

AU - Aller, K.

AU - Littlefair, S. P.

AU - Homeier, D.

AU - Lodieu, N.

AU - Deacon, N.

AU - Marley, M. S.

AU - van Spaandonk, L.

AU - Baker, D.

AU - Allard, F.

AU - Andrei, A. H.

AU - Canty, J.

AU - Clarke, J.

AU - Day-Jones, A. C.

AU - Dupuy, T.

AU - Fortney, J. J.

AU - Gomes, J.

AU - Ishii, M.

AU - Jones, H. R.A.

AU - Liu, M.

AU - Magazzú, A.

AU - Marocco, F.

AU - Murray, D. N.

AU - Rojas-Ayala, B.

AU - Tamura, M.

PY - 2013/7

Y1 - 2013/7

N2 - We report the discovery of 76 new T dwarfs from the UKIRT Infrared Deep Sky Survey(UKIDSS) Large Area Survey (LAS). Near-infrared broad-and narrow-band photometry and spectroscopy are presented for the new objects, along withWide-field Infrared Survey Explorer (WISE) andwarm-Spitzer photometry. Proper motions for 128 UKIDSS T dwarfs are presented from a new two epoch LAS proper motion catalogue. We use these motions to identify two new benchmark systems: LHS 6176AB, a T8p+M4 pair and HD 118865AB, a T5.5+F8 pair. Using age constraints from the primaries and evolutionary models to constrain the radii, we have estimated their physical properties from their bolometric luminosity. We compare the colours and properties of known benchmark T dwarfs to the latest model atmospheres and draw two principal conclusions. First, it appears that the H - [4.5] and J - W2 colours are more sensitive to metallicity than has previously been recognized, such that differences in metallicity may dominate over differences in Teffwhen considering relative properties of cool objects using these colours. Secondly, the previously noted apparent dominance of young objects in the late-T dwarf sample is no longer apparent when using the new model grids and the expanded sample of late-T dwarfs and benchmarks. This is supported by the apparently similar distribution of late-T dwarfs and earlier type T dwarfs on reduced proper motion diagrams that we present. Finally, we present updated space densities for the late-T dwarfs, and compare our values to simulation predictions and those from WISE.

AB - We report the discovery of 76 new T dwarfs from the UKIRT Infrared Deep Sky Survey(UKIDSS) Large Area Survey (LAS). Near-infrared broad-and narrow-band photometry and spectroscopy are presented for the new objects, along withWide-field Infrared Survey Explorer (WISE) andwarm-Spitzer photometry. Proper motions for 128 UKIDSS T dwarfs are presented from a new two epoch LAS proper motion catalogue. We use these motions to identify two new benchmark systems: LHS 6176AB, a T8p+M4 pair and HD 118865AB, a T5.5+F8 pair. Using age constraints from the primaries and evolutionary models to constrain the radii, we have estimated their physical properties from their bolometric luminosity. We compare the colours and properties of known benchmark T dwarfs to the latest model atmospheres and draw two principal conclusions. First, it appears that the H - [4.5] and J - W2 colours are more sensitive to metallicity than has previously been recognized, such that differences in metallicity may dominate over differences in Teffwhen considering relative properties of cool objects using these colours. Secondly, the previously noted apparent dominance of young objects in the late-T dwarf sample is no longer apparent when using the new model grids and the expanded sample of late-T dwarfs and benchmarks. This is supported by the apparently similar distribution of late-T dwarfs and earlier type T dwarfs on reduced proper motion diagrams that we present. Finally, we present updated space densities for the late-T dwarfs, and compare our values to simulation predictions and those from WISE.

KW - Stars: low-mass

KW - Surveys-brown dwarfs

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DO - 10.1093/mnras/stt740

M3 - Article

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76 T dwarfs from the UKIDSS LAS: Benchmarks, kinematics and an updated space density

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Keywords

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