Space Science Bldg, Room 525
1629 E. University Blvd
Tucson, AZ 85721-0092
Phone: (520) 626-3806
Fax: (520) 621-4933
Web Site:

Current Course
For Students
Travel Links
Bicycle Touring

For Jennifer


I'm interested in the complex interplay of physical processes that shape and evolve planetary atmospheres. Much of my attention focuses on Saturn's largest moon Titan, which with clouds, rain and lakes uniquely resembles Earth. Yet the weather on Titan proceeds with natural gas condensing in a thick atmosphere that is dimly powered by the Sun. The condensable is constantly depleted by UV photolysis. So how does Titan's weather & climate proceed? I address these questions with both observations and physical models of planetary atmospheres, which include radiative transfer, thermodynamical and simple chemical calculations. Observations include both spacecraft measurments (e.g. Voyager and Cassini/Huygens) as well as ground-based facilities, most recently, KECK, CTIO, and IRTF. A more recent fascinatation concerns the structure & composition of extrasolar planets. Instead of a mere 8 planets, several hundred exoplanets have been detected, with the number growing exponentially. Here we begin the ultimate game of comparative planetology with radiative transfer analyses of Jupiter sized exoplanets that orbit 100 times closer to their stars than does Jupiter to the Sun. These are easiest to measure right now. We'd like to know their compositions, structures, chemistry & dynamics. The idea is to extend this study to smaller planets, eventually perhaps to another Earthlike thing.

Titan Exoplanets Jovian Planets Press
--------------------------------------------------------------- Click on image for eprints --------------------------------------------------------