Dr. Peter Bodenheimer and his colleague at the University of California, Santa Cruz, Dr. Douglas Lin will use theoretical techniques to study the progression through the process of star formation to the formation of planets. The theoretical models are constrained by the properties of the planetary system as well as by the rich observational information now available regarding young stellar objects. The origin and evolution of the solar nebula and the formation of the planets provides a challenging problem for the theorist. Theories must explain extensive compilations of observational data, ranging from meteoritic abundance anomalies to the properties of outflows from young stars. Recently there has been a rapid accumulation of infrared and ultraviolet data from T Tauri stars, which has led to the strengthening of the hypothesis that accretion disks are present around many of these objects. These disks may be protoplanetary disks. A wide variety of physical processes is involved and must be incorporated into theoretical studies of star and planet formation. Drs. Bodenheimer and Lin concentrate on the formation and evolution of the solar nebula itself. Significant progress is being made with the aid of enhanced interdisciplinary contact and improved computer facilities.