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

May 2012 • 2012MNRAS.422.1922P

Authors • 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.

Abstract • 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 T_eff= 680 ± 55 K and a mass of 20-50M_Jup. 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.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2012MNRAS.422.1922P
• PDF https://academic.oup.com/mnras/pdf-lookup/doi/10.1111/j.1365-2966.2012.20549.x
• PREPRINT http://arxiv.org/abs/1201.3243
• DATA http://archive.eso.org/bin/ads2eso?2012MNRAS.422.1922P
• DATA https://archive.gemini.edu/searchform/publication=2012MNRAS.422.1922P
• DATA https://irsa.ipac.caltech.edu/bibdata/2012/P/2012MNRAS.422.1922P.html
• ELECTR http://dx.doi.org/10.1111/j.1365-2966.2012.20549.x