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My interests include the interiors and atmospheres of planets (mostly giant planets) in and out of the solar system. I work to understand planets as a class of astrophysical objects. Mostly I'm a modeler and theorist, with a few additional observational projects.

  1. The Kepler Mission. The primary goal of this NASA space telescope is to measure the frequency of Earth-size planets in Earth-like orbits around Sun-like stars. This may be the most important number in the history of astronomy. I am a science team member tasked with helping to understand what mass and radius measurements tell us about the structure of detected planets, as well as to interpret observations of optical (reflected) light from the close-in hot Jupiter planets. I will be at the March 5, 2009, launch in Florida.
  2. Thermal evolution models of extrasolar giant planets (EGPs), Jupiter, and Saturn. What is the luminosity of these planets post-formation, when they are easiest to detect? What is the current distribution of heavy elements and helium in their interiors, and how does this change with time? Do all giant planets possess cores of ice and rock, and what does this tell us about their formation? Can they be tidally disrupted? There are now known to be 50+ planets that transit their parent star, allowing us to measure their radii, masses, and densities.
  3. Calculations of the atmospheric structure and spectra of all kinds of planets. What is the day-night temperature contrast of hot Jupiters planets, that orbit at ~0.05 AU from their parent stars? What are the main molecular absorbers in these atmospheres? How well can we constrain the chemical abundances of these atmospheres with data from the Spitzer Space Telescope or the future James Webb Space Telescope?
  4. Determinations of the detectabity of EGP properties through transit photometry. Can planetary ring systems be detected? The oblateness of a planet, which sheds light on its structure? Planetary composition such as the ice-to-rock ratio? I've worked on these issues, particularly in collaboration with Jason Barnes.

UCSC is a great place for theoretical astrophysics as well as planetary sciences. I am a member of Theoretical Astrophysics Santa Cruz (TASC) as well as the Center for the Origin, Dynamics, and Evolution of Planets (