Transit timing observations from Kepler. I.

NASA's Kepler mission has identified 1235 transiting planet candidates. The method of transit timing variations (TTVs) has already confirmed seven planets in two planetary systems.

We perform a transit timing analysis of the Kepler planet candidates. We find that at least ~11% of planet candidates currently suitable for TTV analysis show evidence suggestive of TTVs, representing at least ~65 TTV candidates. In all cases, the time span of observations must increase for TTVs to provide strong constraints on planet masses and/or orbits, as expected based on N-body integrations of multiple transiting planet candidate systems (assuming circular and coplanar orbits).