The dust properties of eight debris disk candidates as determined by submillimeter photometry

The nature of far-infrared dust emission toward main-sequence stars, whether interstellar or circumstellar, can be deduced from submillimeter photometry. We present JCMT/SCUBA flux measurements at 850 mu m toward eight stars with large photospheric excesses at 60-100 mu m. Five sources were detected at 3 sigma or greater significance and one was marginally detected at 2.5 sigma. The inferred dust masses and temperatures range from 0.033 to 0.24 M-circle plus and 43-65 K, respectively. The frequency behavior of the opacity, tau(v) proportional to v(beta), is relatively shallow, beta < 1. These dust properties are characteristic of circumstellar material, most likely the debris from planetesimal collisions. The two nondetections have lower temperatures, 35-8 K, and steeper opacity indices, beta > 1: 5, that are more typical of interstellar cirrus. The confirmed disks all have inferred diameters less than or similar to 2, most lie near the upper envelope of the debris disk mass distribution, and four are bright enough to be feasible for high-resolution imaging.