Abstract

Observations over a wide wavelength range provide diagnostic information on protoplanetary disks, but the submillimeter regime is especially important because (1) optically thin dust emission probes particles through the entire disk, including the cold midplane, (2) these are the longest wavelengths where dust is readily detectable, and therefore the last direct link on the chain of sizes from sub-micron interstellar particles to planetesimals, (3) aligned dust particles can produce polarized emission that traces the magnetic field, and (4) spectral line emission from a variety of species show the detailed disk kinematics and constrain nebular chemistry. I will describe recent results from the Submillimeter Array that take advantage of several of these key features, with implications for disk structure, planet forming potential, and the physics of accretion. In particular, I will discuss a high resolution (0.3 arcsec = 40 AU) 870 micron survey of dust continuum emission from young disks in the Ophiuchus star-forming region, where we have used 2D radiative transfer calculations to fit simultaneously the resolved submillimeter data and the broadband spectral energy distributions with a parametric model in an effort to characterize the viscous properties and the likelihood of future (and perhaps even past) planet formation in these disks.