I’m a Professor of Astronomy at the California Institute of Technology — Caltech.
I am interested in the formation and evolution of planets orbiting stars other than the Sun. My team discovers and characterizes these extrasolar planets using telescopes in Hawaii, California, and in space. I approach this as an observer studying the physical and orbital characteristics of individual planetary systems and the patterns of their ensemble physical properties. With thousands of planetary systems for comparison, we place our Solar System in a broader context.
I am particularly interested in the diversity of small planets. Within our Solar System, Neptune and Earth are the archetypal small planets, representing low-density ice giants and high-density rocky planets. In extrasolar systems we see a much greater diversity of structure and composition owing to broadly varying admixtures of the basic planetary ingredients of hydrogen gas, water, rock, and iron.