Presentation #103.04 in the session Exoplanet Dynamics 1.
The first discovered extrasolar worlds — giant, “hot Jupiter” planets on short-period orbits — came as a surprise to solar-system-centric models of planet formation, prompting the development of new theories for planetary system evolution. The near-absence of observed nearby planetary companions to hot Jupiters has been widely quoted as evidence in support of high-eccentricity tidal migration: a framework in which hot Jupiters form further out in their natal protoplanetary disks before being thrown inward with extremely high eccentricities, stripping systems of any close-in planetary companions. In this work, we present new results from a search for transit timing variations across the full four-year Kepler dataset, demonstrating that at least 12±6% of hot Jupiters have a nearby planetary companion. This subset of hot Jupiters is expected to have a quiescent dynamical history such that the systems could retain their nearby companions. We also demonstrate a ubiquity of nearby planetary companions to warm Jupiters (>70±16%), indicating that warm Jupiters typically form quiescently. In light of these findings, we propose the “eccentric migration” framework to explain the diverse observational configurations of short-period giant planets through post-disk dynamical evolution in compact multi-planet systems. Our framework suggests that hot Jupiters are the final stage of giant planets with diverse eccentricities, excited by other planets in the same systems.