Dr. Geoffrey Blake (Calfornia Institute of Technology) will lead a collaborative research program with researchers at Leiden University that will utilize the Keck Near Infrared Spectrometer (Keck-NIRSPEC) and the Very Large Telescope Cryogenic High-Resolution Infrared Echelle Spectrograph (VLT-CRIRES) to study the properties and evolution of the gas in protoplanetary disks. Circumstellar disks around young stars provide the pivotal link between star formation and (exo)-planetary science. The physical and chemical structures of these disks, along with their transport properties and evolutionary timescales, play a central role in determining what sort of planetary system, if any, can be formed. Probes of the gas in the inner few tens of Astronomical Units (AU) (the planet-building zone) are particularly needed to distinguish between competing planetary formation models. While the direct imaging of the gas in such regions lies several years into the future, infrared spectroscopy and spectro-astrometry provide an alternative route. Dr. Blake, and others, have recently shown that the fundamental rovibrational emission from carbon monoxide near 4.7 µm provides a widely observable diagnostic of the gas in the 0.5-50 AU region of circumstellar disks.
The radiative transfer tools to be developed as part of this proposal will benefit the entire astronomical community. The results of this research project will guide observations with the next generation of microwave/THz and infrared telescopes, and should enable detailed and quantitative models to be constructed of the planet-forming regions of circumstellar disks. This program will also push ground-based infrared spectroscopy and spectro-astrometry to their limits, and will require the optimization of data acquisition, calibration, and reduction routines to achieve a dynamic range close to that imposed by photon statistics. Such routines will be of use to a wide range of observational programs, including infrared radial velocity efforts and the characterization of extrasolar planetary atmospheres from transit measurements. At least four graduate students and several undergraduates will be trained in an exceptionally interdisciplinary manner as part of this research program. Dr. Blake's group is also highly involved in the Caltech Science for Early Educational Development and The Caltech Precollege Science Initiative K-12 educational programs, and is developing new teaching modules for a variety of grade levels.
