Program: GN-2012B-Q-61

Despite the fact that many radial velocity and direct imaging studies suggest a deficit of brown dwarf companions to (solar-type) stars at a range of orbital separations, recent higher-contrast observations hint at a population of substellar companions, with mass ratios as low as ~0.01, particularly around >1 Msun stars. These objects (some of which have masses near and below 15Mjup) may represent the bottom end of the stellar companion mass function or the top end of the planet population, though both scenarios pose challenges to conventional formation models. Motivated by these issues, we proposed an ALTAIR/NIRI survey of 70 target in the Taurus star-forming region in 2011B (GN-2011B-Q-8). Only 38 of those stars were observed, due to the Band-3 allocation. Here we propose to (1) perform follow-up observations of the best two candidates found during 2011B and (2) complete the observations of the full sample we originally proposed for, enlarged up to 80 stars, as suggested by the TAC. This final sample will cover a wide range of masses, to resolve new stellar and substellar companions, thus providing useful benchmarks for the theoretical models.