Program: GN-2009A-DD-3

We propose to obtain follow-up JHK imaging of a 15 Mjup companion candidate that we have identified around a 5 Msun star in the 5 Myr-old Upper Scorpius star-forming region. The candidate companion is located at a separation of 2.68", corresponding to ~330 AU at the distance of the primary. The proposed observations are necessary to verify the common proper motion of the candidate companion and to verify whether its near-infrared colors are consistent with a young, low-mass object. If confirmed, this companion would have the lowest mass ratio (q~0.003) of any companion ever imaged around a star, and it would be the first low-mass brown dwarf companion around such a massive star.