Presentation #117.05 in the session “Exoplanets 1”.
We present the discovery of Kepler-88d (P=1403±14 days, Msini = 3.04±0.13 MJ, e = 0.41±0.03) based on six years of radial velocity follow-up from the W. M. Keck Observatory High Resolution Echelle Spectrometer. Kepler-88 has two previously identified planets: Kepler-88b (KOI-142.01) transits in the NASA Kepler photometry and has very large transit timing variations (TTVs), which led to the moniker “The King of TTVs.” In previous studies, a dynamical analysis of the TTVs uniquely identified the orbital period and mass of the perturbing planet Kepler-88 c, which was subsequently confirmed with RVs; however, the previous studies did not find the third planet presented in this paper. We performed photodynamical modeling to simultaneously fit 17 quarters Kepler photometry and six years of RV data, yielding the most precise planet masses and orbital properties yet for all three planets. As one of the most dynamically constrained multi-planet systems with a transiting planet, Kepler-88 provides an important benchmark for understanding planet formation and evolution.