An Infrared Coronagraphic Survey for Substellar Companions

We have used the F160W filter (1.4–1.8 μm) 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 30 M J companion at separations between 15 and 200 AU. A 5 M J 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 1 M J , 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).