Using FORS2 on the Very Large Telescope, we have astrometrically monitored over a period of two months the two components of the brown dwarf system WISE J104915.57-531906.1, the closest one to the Sun. Our astrometric measurements - with a relative precision at the milli-arcsecond scale - allow us to detect the orbital motion and derive more precisely the parallax of the system, leading to a distance of 2.020+/-0.019 pc. The relative orbital motion of the two objects is found to be perturbed, which leads us to suspect the presence of a substellar companion around one of the two components. We also perform VRIz photometry of both components and compare with models. We confirm the flux reversal of the T dwarf.
H.M.J. Boffin, D. Pourbaix, K. Muzic, V.D. Ivanov, R. Kurtev, Y. Beletsky, A. Mehner, J.P. Berger, J.H. Girard, D. Mawet (Submitted on 4 Dec 2013)
Comments: Accepted in A&A Letter
Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:1312.1303 [astro-ph.SR] (or arXiv:1312.1303v1 [astro-ph.SR] for this version)
Submission history From: Henri M. J. Boffin [view email] [v1] Wed, 4 Dec 2013 19:54:54 GMT (1815kb,D)