Molecular Astrophysics and Star/Planet Formation
The research interests of the students and postdoctoral fellows with whom I work are broadly centered on star and, especially, planet formation. While we carry out observational, theoretical and laboratory programs, the common tool we wield most effectively is spectroscopy. We use molecular spectra both as probes of the environments in which solar systems are assembled and to investigate the fascinating chemistry that occurs long before planetary surfaces are available.
Our observing programs rely heavily on the wonderful suite of telescopes available to Caltech astronomers and planetary scientists, most importantly the Keck telescopes, the CSO, and CARMA. Over the past few years we have been actively involved in extensive Spitzer IRS surveys that have examined the IR spectra of circumstellar disks, and we will complement this work with far-IR data using the Herschel Space Telescope over the coming years. Combined with Keck NIRSPEC studies, our Spitzer observations have shown that the mid-IR spectroscopy of the disks around young stars can be used to examine both the dust and gas content of their near-surface regions at planet-forming radii. These extraordinarily rich spectra contain clues as to the movement and fate of volatile species such as water in the disk (see figure at right), and are thus providing a new window into the processes that build planetary systems. Follow-on work with CARMA, ALMA and Herschel will extend our reach into the outer regions of disks analogous to our own Kuiper Belt.
In the laboratory, we have developed state-of-the-art TeraHertz-Time Domain Spectroscopy (THz-TDS) systems that can interrogate the optical properties of materials from wavelengths ranging from 50 to 1000 microns and over a temperature range of 10-600 K. The temporal resolution of the spectrometers is <100 femtoseconds. We are using these new tools to examine the long wavelength properties of interstellar dust analogs along with the large amplitude vibrational modes of complex molecules that will be uniquely available to instruments aboard Herschel, SOFIA and the CSO.
Recently, I became Caltech‚ Master of Student Houses (MOSH). In addition to helping promote student-faculty interactions around campus, my wife and I have the opportunity to regularly welcome groups of students to the MOSH house. We hope to see you there some day!
[Image credits: Bob Paz; Klaus Pontoppidan]