Two new ultracool benchmark systems from WISE+2MASS

May 2013 • 2013MNRAS.431.2745G

Authors • Gomes, J. I. • Pinfield, D. J. • Marocco, F. • Day-Jones, A. C. • Burningham, B. • Zhang, Z. H. • Jones, H. R. A. • van Spaandonk, L. • Weights, D.

Abstract • We have used the Two-Micron All-Sky Survey and the Wide-field Infrared Survey Explorer to look for ultracool dwarfs that are part of multiple systems containing main-sequence stars. We cross-matched L dwarf candidates from the surveys with Hipparcos and Gliese stars, finding two new systems. The first system, G255-34AB, is an L2 dwarf companion to a K8 star, at a distance of 36 pc. We estimate its bolometric luminosity as log L/L_⊙ = -3.78 ± 0.045 and T_eff = 2080 ± 260 K. The second system, GJ499ABC, is a triple, with an L5 dwarf as a companion to a binary with an M4 and K5 star. These two new systems bring the number of L dwarf plus main-sequence star multiple systems to 24, which we discuss. We consider the binary fraction for L dwarfs and main-sequence stars, and further assess possible unresolved multiplicity within the full companion sample. This analysis shows that some of the L dwarfs in this sample might actually be unresolved binaries themselves, since their M_J appears to be brighter than the expected for their spectral types.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2013MNRAS.431.2745G
• PDF https://academic.oup.com/mnras/pdf-lookup/doi/10.1093/mnras/stt371
• PREPRINT http://arxiv.org/abs/1303.2268
• DATA https://irsa.ipac.caltech.edu/bibdata/2013/G/2013MNRAS.431.2745G.html
• ELECTR https://doi.org/10.1093%2Fmnras%2Fstt371