The Fate of Scattered Planets

Abstract

As gas giant planets evolve, they may scatter other planets far from their original orbits to produce hot Jupiters or rogue planets that are not gravitationally bound to any star. Here, we consider planets cast out to large orbital distances on eccentric, bound orbits through a gaseous disk. With simple numerical models, we show that super-Earths can interact with the gas through dynamical friction to settle in the remote outer regions of a planetary system. Outcomes depend on planet mass, the initial scattered orbit, and the evolution of the time-dependent disk. Efficient orbital damping by dynamical friction requires planets at least as massive as the Earth. More massive, longer-lived disks damp eccentricities more efficiently than less massive, short-lived ones. Transition disks with an expanding inner cavity can circularize orbits at larger distances than disks that experience a global (homologous) decay in surface density. Thus, orbits of remote planets may reveal the evolutionary history of their primordial gas disks. A remote planet with an orbital distance ~100 AU from the Sun is plausible and might explain correlations in the orbital parameters of several distant trans-Neptunian objects.

ApJ, accepted, 23 pages, 5 figures

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Cited by in corpus (8)

• Population-Level Eccentricity Distributions of Imaged Exoplanets and Brown Dwarf Companions: Dynamical Evidence for Distinct Formation Channels
• New Extreme Trans-Neptunian Objects: Towards a Super-Earth in the Outer Solar System
• Solar System Physics for Exoplanet Research
• Formation of Super-Earth Mass Planets at 125-250 AU from a Solar-type Star
• A Pluto--Charon Sonata: Dynamical Limits on the Masses of the Small Satellites
• A Pluto-Charon Concerto: An Impact on Charon as the Origin of the Small Satellites
• VLT/SPHERE survey for exoplanets around young, early-type stars including systems with multi-belt architectures
• Formation of wide-orbit gas giants near the stability limit in multi-stellar systems