The Impact of Transit Observations on Planetary Physics
  We highlight the importance of transit observations on understanding the physics of planetary atmospheres and interiors. Transmission spectra and emission spectra allow us to characterize this exotic atmospheres, which possess TiO, VO, H2O, CO, Na, and K, as principal absorbers. We calculate mass-radius relations for water-rock-iron and gas giant planets and examine these relations in light of current and future transit observations. A brief review is given of mechanisms that could lead to the large radii observed for some transiting planets. 
Jonathan J. Fortney