N-body simulations of a warm Jupiter near resonance with a sub-Neptune

While very few hot Jupiters are known to have nearby planetary companions, warm Jupiters with nearby small planets are much more common. We have identified an interior, non-transiting warm Jupiter near the 2:1 resonance with a transiting sub-Neptune originally detected by Kepler. The near-resonant architecture is unusual among other warm Jupiters, and it allows us to explore the system in more detail. We simulate this peculiar system with the REBOUND software package to test its stability and determine its dynamical evolution. In particular, we focus on varying parameters such as the mutual inclination and eccentricities while requiring long-term stability and consistency with the observed Kepler transit durations. From this, we can refine the parameters of the Jupiter, which are not precisely determined from the RVs alone. We find that the system can be stable within the known constraints set by Kepler and RV data, but we rule out many configurations with high eccentricities or mutual inclinations beyond a few degrees. The near-circular, coplanar configuration may be consistent with an in-situ formation.