Discovery of the benchmark metal-poor T8 dwarf BD +01° 2920B

Pinfield, D. J.; Burningham, B.; Lodieu, N.; Leggett, S. K.; Tinney, C. G.; van Spaandonk, L.; Marocco, F.; Smart, R.; Gomes, J.; Smith, L.; Lucas, P. W.; Day-Jones, A. C.; Murray, D. N.; Katsiyannis, A. C.; Catalan, S.; Cardoso, C.; Clarke, J. R. A.; Folkes, S.; Gálvez-Ortiz, M. C.; Homeier, D.; Jenkins, J. S.; Jones, H. R. A.; Zhang, Z. H.
Bibliographical reference

Monthly Notices of the Royal Astronomical Society, Volume 422, Issue 3, pp. 1922-1932.

Advertised on:
5
2012
Number of authors
23
IAC number of authors
1
Citations
66
Refereed citations
59
Description
We have searched the Wide-field Infrared Survey Explorer first data release for widely separated (≤10 000 au) late T dwarf companions to Hipparcos and Gliese stars. We have discovered a new binary system containing a K-band suppressed T8p dwarf WISEP J142320.86+011638.1 and the mildly metal poor ([Fe/H] =-0.38 ± 0.06) primary BD +01° 2920 (HIP 70319), a G1 dwarf at a distance of 17.2 pc. This new benchmark has Teff= 680 ± 55 K and a mass of 20-50MJup. Its spectral properties are well modelled except for known discrepancies in the Y and K bands. Based on the well-determined metallicity of its companion, the properties of BD +01° 2920B imply that the currently known T dwarfs are dominated by young low-mass objects. We also present an accurate proper motion for the T8.5 dwarf WISEP J075003.84+272544.8.
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