Planet-Planet Scattering and ZLK Migration -- The Dynamical History of HAT-P-11

The two planets of the HAT-P-11 system represent fascinating dynamical puzzles due to their significant eccentricities and orbital misalignments. In particular, HAT-P-11 b is on a close-in orbit that tides should have circularized well within the age of the system. Here we propose a two-step dynamic...

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Bibliographic Details
Published in:arXiv.org 2024-12
Main Authors: Lu, Tiger, An, Qier, Li, Gongjie, Millholland, Sarah C, Rice, Malena, Brandt, G Mirek, Brandt, Timothy D
Format: Article
Language:English
Subjects:
Misalignment
Planetary orbits
Scattering
Online Access:Get full text
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Summary:The two planets of the HAT-P-11 system represent fascinating dynamical puzzles due to their significant eccentricities and orbital misalignments. In particular, HAT-P-11 b is on a close-in orbit that tides should have circularized well within the age of the system. Here we propose a two-step dynamical process that can reproduce all intriguing aspects of the system. We first invoke planet-planet scattering to generate significant eccentricities and mutual inclinations between the planets. We then propose that this misalignment initiated von-Zeipel-Lidov-Kozai cycles and high-eccentricity migration that ultimately brought HAT-P-11 b to its present-day orbit. We find that this scenario is fully consistent only when significant tidally-driven radius inflation is accounted for during the tidal migration. We present a suite of N-body simulations exploring each phase of evolution and show that this scenario is consistent with all observational posteriors and the reported age of the system.
ISSN:2331-8422