An Infrared Coronagraphic Survey for Substellar Companions

We have used the F160W filter (1.4-1.8 mm) and the coronagraph on the Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope to survey 45 single stars with a median age of 0.15 Gyr, an average distance of 30 pc, and an average H magnitude of 7 mag. For the median age we were capable of detecting a 30MJ companion at separations between 15 and 200 AU. A 5MJ object could have been detected at 30 AU around 36% of our primaries. For several of our targets that were less than 30 Myr old, the lower mass limit was as low as 1MJ, well into the high mass planet region. Results of the entire survey include the proper-motion verification of five low-mass stellar companions, two brown dwarfs (HR7329B and TWA5B), and one possible brown dwarf binary (Gl 577B/C).