The project is developing new theoretical models for the formation of extrasolar gas giant planets in different planet formation environments. The models follow the growth of a planetary core in an evolving protoplanetary disk up to the epoch when rapid gas accretion ensues yielding a giant planet. How fast growth occurs depends upon the physical conditions in the protoplanetary disk (temperature, density etc.), and on the mobility of planetary cores and planetesimals which can migrate in orbital radius as a consequence of gravitational torques from the disk. Multidimensional numerical simulations of turbulent magnetized disks are used to characterize this mobility, and the results incorporated into one-dimensional time-dependent models for planetary growth via core accretion. The timescale for the growth of gas giant planets is being evaluated in different environments, for example around stars of different masses and metallicities. These theoretical estimates of planetary growth times may be compared to observational determinations of protoplanetary disk lifetimes to predict how the frequency of massive planet formation varies across disk environments. Existing observations are used to constrain the models, while the broader predictions will be testable using data from forthcoming ground and space-based searches for extrasolar planets.
