Moorhead, Althea V., Ford, Eric B., Morehead, Robert C., Rowe, Jason, Borucki, William J., Batalha, Natalie M., Bryson, Stephen T., Caldwell, Douglas A., Fabrycky, Daniel C., Gautier, Thomas N., III, Koch, David G., Holman, Matthew J., Jenkins, Jon M., Li, Jie, Lissauer, Jack J., Lucas, Philip, Marcy, Geoffrey W., Quinn, Samuel N., Quintana, Elisa V., Ragozzine, Darin, Shporer, Avi, Still, Martin, and Torres, Guillermo. 2011. "The Distribution of Transit Durations for Kepler Planet Candidates and Implications for Their Orbital Eccentricities." The Astrophysical Journal Supplement Series, 197, (1). https://doi.org/10.1088/0067-0049/197/1/1.
Doppler planet searches have discovered that giant planets follow orbits with a wide range of orbital eccentricities, revolutionizing theories of planet formation. The discovery of hundreds of exoplanet candidates by NASA's Kepler mission enables astronomers to characterize the eccentricity distribution of small exoplanets. Measuring the eccentricity of individual planets is only practical in favorable cases that are amenable to complementary techniques (e.g., radial velocities, transit timing variations, occultation photometry). Yet even in the absence of individual eccentricities, it is possible to study the distribution of eccentricities based on the distribution of transit durations (relative to the maximum transit duration for a circular orbit). We analyze the transit duration distribution of Kepler planet candidates. We find that for host stars with T eff > 5100 K we cannot invert this to infer the eccentricity distribution at this time due to uncertainties and possible systematics in the host star densities. With this limitation in mind, we compare the observed transit duration distribution with models to rule out extreme distributions. If
