Characterizing Planetary Populations with Kepler and Future Exoplanet Surveys

Eric Ford (Penn State)

April 27, 2017

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Abstract: For centuries, planet formation theories were fine tuned to explain the details of solar system. The diversity of planetary systems uncovered by Doppler surveys challenged previous theories and led to insights into planet formation, orbital migration and the excitation of orbital eccentricities and inclinations. NASA”s Kepler mission has identified over a thousand systems with multiple transiting planet candidates, including many small and potentially rocky planets. These planets are enabling scientists to characterize the distribution of planetary properties and the architectures of planetary systems. In addition, transit timing variations (TTVs) provide an excellent tool to characterize the masses and orbits of dozens of small planets, including many at orbital periods beyond the reach of both Doppler surveys and photoevaporation-induced atmospheric loss. Dynamical modeling of these systems has identified some “supper-puffy” planets, i.e., low mass planets with surprisingly large radii and low densities. These discoveries challenge traditional planet formation theories and invite a new framework for understanding planet formation. I will describe some of the challenges in interpreting these discoveries properly and how recent advances in statistical methodology can overcome these challenges.