PHL 5038: a spatially resolved white dwarf brown dwarf binaryP. R. Steele1, M. R. Burleigh1, J. Farihi1, B. T. Gänsicke2, R. F. Jameson1, P. D. Dobbie3, and M. A. Barstow1
1 Department of Physics & Astronomy, University of Leicester, Leicester, LE1 7RH, UK
2 Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
3 Anglo-Australian Observatory, PO Box 296, Epping, Sydney, NSW 1710, Australia
Recieved 21 January 2009 / Accepted 19 March 2009
A near-infrared excess is detected at the white dwarf PHL 5038 in UKIDSS photometry, consistent with the presence of a cool, substellar companion. We have obtained H- and K-grism spectra and images of PHL 5038 using NIRI on Gemini North. The target is spatially and spectrally resolved into two components: an 8000 K DA white dwarf, and a likely L8 brown dwarf companion, separated by . The spectral type of the secondary was determined using standard spectral indices for late L and T dwarfs. The projected orbital separation of the binary is 55 AU, so it becomes only the second known wide WD+dL binary to be found after GD 165AB. This object could potentially be used as a benchmark for testing substellar evolutionary models at intermediate to older ages.
Key words: white dwarfs -- stars: low-mass, brown dwarfs -- binaries: general -- binaries: visual
© ESO 2009