Discovery of the benchmark metal-poor T8 dwarf BD +01° 2920B
/ Authors
D. Pinfield, B. Burningham, N. Lodieu, N. Lodieu, S. Leggett, C. Tinney, L. V. Spaandonk, F. Marocco, R. Smart, J. Gomes
and 15 more authors
L. Smith, P. Lucas, A. Day-Jones, D. Murray, A. Katsiyannis, S. Catalan, C. Cardoso, C. Cardoso, J. Clarke, S. Folkes, M. Gálvez-Ortiz, D. Homeier, J. S. Jenkins, H. R. Jones, Z. Zhang
/ Abstract
We have searched the WISE first data release for widely separated (610,000AU) late T dwarf companions to Hipparcos and Gliese stars. We have discovered a new binary system containing a K-band suppressed T8p dwarf WISEP J1423+0116 and the mildly metal poor ([Fe/H]= 0.38±0.06) primary BD+01 2920 (Hip 70319), a G1 dwarf at a distance of 17.2pc. This new benchmark has Teff=680±55K 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 lowmass objects. We also present an accurate proper motion for the T8.5 dwarf WISEP J075003.84+272544.8.
Journal: Monthly Notices of the Royal Astronomical Society