PHL 5038: a spatially resolved white dwarf + brown dwarf binary
Abstract
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 0.94 arcsec. 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.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- June 2009
- DOI:
- 10.1051/0004-6361/200911694
- arXiv:
- arXiv:0903.3219
- Bibcode:
- 2009A&A...500.1207S
- Keywords:
-
- white dwarfs;
- stars: low-mass;
- brown dwarfs;
- binaries: general;
- binaries: visual;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 5 pages, 3 figures, accepted to A&