Substellar Companions to Nearby Stars from NICMOS Surveys

A coronagraphic imaging survey of 65 nearby stars was conducted using the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope by the Instrument Definition Team. Using these guaranteed time observations we searched for very low mass stellar and substellar (extra-solar giant planet and brown dwarf) companions to young main sequence and late M dwarf stars. Nineteen additional stars, similarly observed in our circumstellar disk program, were also examined for evidence of companions. We discuss the large depth and dynamic range of these surveys which have given rise to several putative and confirmed detections. Using follow-up spectrographic observations obtained with the Space Telescope Imaging Spectrograph (STIS) we have begun to characterize the physical nature of the objects found in the companion search program.