  Only very few solar-type stars exhibiting an infrared excess and harbouring
planets are known to date. Indeed, merely a single case of a star-planet-disk
system has previously been detected at submillimeter (submm) wavelengths.
Consequently, one of our aims is to understand the reasons for these poor
statistics, i.e., whether these results reflected the composition and/or the
physics of the planetary disks or were simply due to observational bias and
selection effects. Finding more examples would be very significant. The
selected target, q1 Eri, is a solar-type star, which was known to possess a
planet, q1 Eri b, and to exhibit excess emission at IRAS wavelengths, but had
remained undetected in the millimeter regime. Therefore, submm flux densities
would be needed to better constrain the physical characteristics of the
planetary disk. Consequently, we performed submm imaging observations of q1
Eri. The detected dust toward q1 Eri at 870 micron exhibits the remarkable fact
that the entire SED, from the IR to mm-wavelengths, is fit by a single
temperature blackbody function (60 K). This would imply that the emitting
regions are confined to a narrow region (ring) at radial distances much larger
than the orbital distance of q1 Eri b, and that the emitting particles are
considerably larger than some hundred micron. However, the 870 micron source is
extended, with a full-width-half-maximum of roughly 600 AU. Therefore, a
physically more compelling model also invokes a belt of cold dust (17 K),
located at 300 AU from the star and about 60 AU wide. The minimum mass of 0.04
Mearth (3 Mmoon) of 1 mm-size icy ring-particles is considerable, given the
stellar age of about 1 Gyr. These big grains form an inner edge at about 25 AU,
which may suggest the presence of an unseen outer planet (q1 Eri c).
