Princeton University/Institute for Advanced Study Planet/Exoplanet Discussion Group

The dynamical history of the eccentric close-in planets remains elusive. I will discuss two distinct populations: (i) the eccentric warm Jupiters (gas giants at ~0.1-1 AU) with outer companions mainly observed in RV surveys; (ii) the eccentric and single-transiting Super-Earths observed by the Kepler spacecraft. First, one intriguing scenario for the formation of the eccentric warm Jupiters termed high-eccentricity migration involves gravitational perturbations with an outer massive companion and tidal dissipation. I will discuss the constraints involving the mutual inclinations between the warm Jupiters and outer planetary companions, and argue that high-eccentricity migration predicts a significantly wider distribution compared to other alternative dynamical history scenarios. I will show that the Gaia’s end-of-mission astrometric measurements combined with the current radial velocity data has the potential to measure the mutual inclinations of a few of these systems with uncertainty levels that will provide an important new test-bed to constrain the origin of this class of planets. Further constraints will be possible for transiting warm Jupiters where the inclination of the outer planet is constrained by Gaia. Second, I will show that the population of eccentric Super Earths can be naturally explained by an instability phase involving outer giant planets. This scenario predicts that eccentric Super Earths should co-exist with distant Jovians, whose presence can be constrained by Gaia.