SIMBAD references

A giant planet was recently discovered around the young star {beta} Pictoris. This planet is the closest to its parent star ever imaged. With an estimated mass of about 9M_Jup and separation of 8-15AU, it explains most of the peculiarities of {beta} Pictoris and its disk. Previous detections were made in the L' band (3.8µm) and at 4.05µm. We recorded new K_s-band data (2.18µm) in order to measure its color and get an additional estimate of its mass and effective temperature Angular differential K_s-band images of {beta} Pictoris were recorded with NaCo in March and April 2010. The companion is detected at K_s. This independently confirms the physical nature of {beta} Pictoris b inferred from the L' and NB_4.05 bands. The increase of the projected separation between October-December 2009 and April 2010 observations is consistent within error bars with the expected orbital motion. Using the absolute K_s photometry, ``hot start'' evolutionary models predict a mass of 7-11M_Jup in agreement with previous estimates. Moreover, this mass is compatible with T_eff=1700±300K derived from the comparison of the K_s-L' color with those generated using synthetic spectra.