A small new group appeared at the Observatory in 1999 to scrutinize the mechanisms of formation of the newly discovered extrasolar planetary systems. Other interests of the group (described in the 1997-1998 Report) include the dynamics of binary star formation, and a range of dust-related topics in Beta Pictoris-type circumstellar dust disks.
Exoplanet discovery (32 non-controversial candidates are known) and exoplanet theory are a booming area of astrophysics. The first multi-planet system around a normal star (ups And), and dust disks in 3 of the 6 studied systems with known exoplanets have been discovered. Theory developed at the Observatory concerns the principles of protoplanet interaction with primordial disks, as one of the leading proposed causes for the very unusual orbital properties of the giant exoplanets. In particular, numerical simulations were done of the important processes of radial planet migration in disks, and eccentricity generation. We developed a new theory of dust migration in optically thin disks, which will find application to the disks such as HR4796 and HD141569 imaged recently by HST, showing a little understood ring-and-gap morphology. We performed one of the first numerical stability analyses of ups And on a 2 Gyr time scale on a mini-supercomputer Hydra built and operated by the group in 1999.