April 30, 1998 CfA Colloquium


Title: Evolutionary Properties of Circumstellar Disks and Extra-solar Planet Formation

Speaker: Steve Beckwith

Abstract: Circumstellar disks are a common property of young stars. Previous work showed that these disks are suitable for the creation of planetary systems having enough mass and time to build large bodies; there is some evidence that particle coagulation is underway in many young disks. A careful analysis of the spectra and spectral energy distributions in the thermal infrared obtained from ISO observations is in accord with recent theories of the disk radiation, showing that the analysis of disk properties should be robust. Additonal ISO observations of cluster stars shows that the planet-building regions, approximately 1 to 5 AU, evolve on similar time scales as the inner parts, disappearing in less than 10 million years. Taken together, the data support the idea that the disks build planetary systems, and there are many such systems in the Galaxy.

Reference for students: Beckwith & Sargent, Nature, vol. 383, p. 139. Jean Collins has copies!