A Search for Exozodiacal Dust and Faint Companions Near Sirius, Procyon,   and Altair with the NICMOS Coronagraph
  We observed Sirius, Altair, and Procyon with the NICMOS Coronagraph on the Hubble Space Telescope to look for scattered light from exozodiacal dust and faint companions within 10 AU from these stars. We did not achieve enough dynamic range to surpass the upper limits set by IRAS on the amount of exo-zodiacal dust in these systems, but we did set strong upper limits on the presence of nearby late-type and sub-stellar companions. 
Marc J. Kuchner (Caltech) and Michael E. Brown (Caltech)