Validating an Improved Photodynamical Analysis of Kepler Multi-Transiting Systems

NASA’s Kepler Space Telescope, launched in 2009 with the primary mission of discovering exoplanets, identified 706 Multi-Transiting Systems (MTSs). Of Kepler’s 706 MTSs, ~200 show evidence for planet-planet interactions in the form of Transit Timing Variations (TTVs), most of which have been studied to estimate planetary masses. However, only ~10 systems have been studied with an advanced photodynamical model that directly uses an n-body integrator to produce a simulated lightcurve. We have developed the publicly-available PhoDyMM (the PhotoDynamical Multi-planet Model) code to support photodynamical analyses. Using PhoDyMM, we have begun to analyze all MTSs in a consistent manner with a goal to create a complete catalog of the planetary parameters of the 1767 planetary candidates of Kepler’s MTSs. Analyzing all MTSs in the same way provides unique insight into the ensemble of planetary physical and orbital parameters. PhoDyMM uses Bayesian parameter inference by employing a Differential Evolution Markov Chain Monte Carlo (DEMCMC) on a high-performance computing cluster. Ensuring the quality of fit of such a large number of systems requires an extensive analysis of the PhoDyMM outputs, including several automatically-customized plots of parameters, likelihoods, residuals, fit quality, etc. We will use these plots and other metrics to validate PhoDyMM by showing that our results are improvements to previously published results on multiple systems.