The Origin of Kepler-419b: A Path to Tidal Migration Via Four-body Secular Interactions

We test the high-eccentricity tidal migration scenario for Kepler-419b, a member of the eccentric warm Jupiter class of planets whose origin is debated. Kepler-419 hosts two known planets (b,c). However, in its current configuration, planet c cannot excite the eccentricity of planet b enough to undergo high-eccentricity tidal migration. We investigate whether the presence of an undiscovered fourth body could explain the orbit of Kepler-419b. We explore the parameter space of this potential third giant planet using a suite of N-body simulations with a range of initial conditions. From the results of these simulations, coupled with observational constraints, we can rule out this mechanism for much of the parameter space of the initial object d conditions. However, for a small range of parameters (masses between 0.5 and 7 m Jup, semimajor axes between 4 and 7.5 au, eccentricities between 0.18 and 0.35, and mutual inclinations near 0°) an undiscovered object d could periodically excite the eccentricity of Kepler-419b without destabilizing the system over 1 Gyr while producing currently undetectable radial velocity and transit timing variation signals.