Caltech has a strong program in these areas. Heather Knutson observes exoplanet atmospheres and has participated in the Spitzer mission. John Johnson participates in Kepler and a variety of exoplanet detection and characterization efforts.
Mike Brown observes bodies in the distant reaches of our own solar system and Geoff Blake observes the planet forming regions and disks around other stars. Shri Kulkarni has a wide-ranging program in astronomy that includes study of small bodies (e.g., asteroids).
We have an effective interaction with astronomers across the road in the Cahill Center for Astronomy and Astrophysics, for example Lynne Hillenbrand and many others.
Exoplanets and Planetary Astronomy