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

作者：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; Galvez Ortiz M C; Homeier D; Jenkins J S; Jones H R A; Zhang Z H

来源：Monthly Notices of the Royal Astronomical Society, 2012, 422(3): 1922-1932.

DOI：10.1111/j.1365-2966.2012.20549.x

• surveys
• brown dwarfs
• stars: low-mass

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 degrees 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 2050MJup. 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 degrees 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.

• 出版日期2012-5