Adaptive optics observations of the T10 ultracool dwarf UGPS J072227.51-054031.2⋆
Centro de Astrobiología, INTA-CSIC, PO Box 78, 28691
Villanueva de la Cañada,
2 European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago 19, Chile
3 Centre for Astrophysics, STRI, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK
Accepted: 17 August 2010
Context. With a spectral type of T10, UGPS J072227.51-054031.2 is one of the coolest objects known to date in the solar neighborhood.
Aims. Multiple systems are relatively common among early and mid-T dwarfs. We search for faint and close companions around UGPS J072227.51-054031.2.
Methods. We have obtained high spatial resolution images in the H and Ks bands using adaptive optics at the Very Large Telescope.
Results. With a Strehl ratio in the range 10−15%, the final images allow us to rule out the presence of a companion brighter than H ≲ 19.4 mag at separation larger than 50 mas, and H ≲ 21.4 mag at separation larger than 01.
Key words: binaries: general / brown dwarfs / techniques: high angular resolution
© ESO, 2010