My interests include the interiors and atmospheres of planets in and out of the solar system. I work to understand planets as classes of astrophysical objects. Mostly I'm a modeler and theorist, with a few additional observational projects.
- 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! Over the years I have been a science team member and close collaborator. Often I've been helping to understand what mass and radius measurements tell us about the structure of detected planets, as well as to interpret observations of optical light from the close-in hot Jupiter planets.
- Thermal evolution models of extrasolar super Earths, giant planets, Jupiter, and Saturn. What is nature and composition of exoplanets? How do they cool over time and when are they easiest to detect? What is the current distribution of rock, iron, water, and possibly 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 planets be tidally disrupted? There are now known to be thousands of planets that transit their parent star, allowing us to measure their radii, and often their masses, and densities.
- Calculations of the atmospheric structure and spectra of all kinds of planets. How do planetary atmospheres show us their planetary composition? How do planets maintain or lose their atmospheres? What is the day-night temperature contrast of tidally locked planets? What are the main molecular absorbers in these atmospheres? How well can we constrain the chemical abundances of these atmospheres with data from current and future telescopes? Currently I'm working from the super-Earth to super-Jupiter mass regime.
- Emission spectra and cloud formation in the coolest brown dwarfs and planets. Astronomers can now find failed stars with temperatures between 500 K and Jupiter's 125 K. We're modeling clouds than range from the exotic (potassium chloride salt) to the common (water) that form in planets and brown dwarfs in this temperature range. I'm a member of the Gemini Planet Imager and LEECH science teams that are finding and characterizing cool planets around nearby young stars.
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 (CODEP).