Otor, Oderah JustinMontet, Benjamin T.Johnson, JohnCharbonneau, DavidCollier-Cameron, AndrewHoward, Andrew W.Isaacson, HowardLatham, DavidLopez-Morales, MercedesLovis, ChristopheMayor, MichelMicela, GiusiMolinari, EmilioPepe, FrancescoPiotto, GiampaoloPhillips, DavidQueloz, DidierRice, KenSasselov, DimitarSégransan, DamienSozzetti, AlessandroUdry, StéphaneWatson, Chris2017-02-222016Otor, Oderah Justin, Benjamin T. Montet, John Asher Johnson, David Charbonneau, Andrew Collier-Cameron, Andrew W. Howard, Howard Isaacson, et al. 2016. The Orbit and Mass of the Third Planet in the Kepler-56 System. The Astronomical Journal 152, no. 6: 165. doi:10.3847/0004-6256/152/6/165.1538-3881http://nrs.harvard.edu/urn-3:HUL.InstRepos:30410816While the vast majority of multiple-planet systems have orbital angular momentum axes that align with the spin axis of their host star, Kepler-56 is an exception: its two transiting planets are coplanar yet misaligned by at least 40 degrees with respect to the rotation axis of their host star. Additional follow-up observations of Kepler-56 suggest the presence of a massive, non-transiting companion that may help explain this misalignment. We model the transit data along with Keck/HIRES and HARPSN radial velocity data to update the masses of the two transiting planets and infer the physical properties of the third, non-transiting planet. We employ a Markov Chain Monte Carlo sampler to calculate the best-fitting orbital parameters and their uncertainties for each planet. We find the outer planet has a period of 1002 ± 5 days and minimum mass of 5.61 ± 0.38 MJup. We also place a 95% upper limit of 0.80 m s−1 yr−1 on long-term trends caused by additional, more distant companions.en-USplanets and satellites: fundamental parametersplanets and satellites: individual: Kepler-56techniques: radial velocitiesJournal Article2017-02-2210.3847/0004-6256/152/6/165