New Submillimeter Limits on Dust in the 55 Cancri Planetary System

We present new, high-sensitivity submillimeter observations toward 55 Cancri, a nearby G8 star with one, or possibly two, known planetary companion(s). Our 850 μm map, obtained with the Submillimeter Common-User Bolometric Array on the James Clerk Maxwell Telescope, shows three peaks of emission at the 2.5 mJy level in the vicinity of the star's position. However, the observed peaks are 25''-40'' away from the star, and a deep R-band optical image reveals faint point sources that coincide with two of the submillimeter peaks. Thus, we do not find evidence of dust emission spatially associated with 55 Cancri. The excess 60 μm emission detected with the Infrared Space Observatory may originate from one or more of the 850 μm peaks that we attribute to background sources. Our new results, together with the Hubble Space Telescope NICMOS coronagraphic images in the near-infrared, place stringent limits on the amount of dust in this planetary system and argue against the existence of a detectable circumstellar dust disk around 55 Cnc.