Uncovering the Rapidly Evolving Orbits of the Dynamic TOI-201 System

TL;DR

This study combines multiple observational techniques and dynamical simulations to analyze the rapidly changing orbits of the TOI-201 exoplanet system, revealing its short-term evolution and underlying dynamical processes.

Contribution

It provides a comprehensive characterization of the TOI-201 system and demonstrates the role of von-Zeipel-Kozai-Lidov oscillations in its orbital evolution.

Findings

The outer companion has a high orbital eccentricity explained by dynamical interactions.

The system's current co-transiting configuration will end in approximately 200 years.

Dynamical simulations favor von-Zeipel-Kozai-Lidov oscillations as the main evolutionary mechanism.

Abstract

Studying planetary interactions in exoplanet systems informs theories of planet formation and evolution, providing essential context for understanding our own solar system. We combine spectroscopy, transit photometry, transit timing variations, and astrometry to characterize the TOI-201 system. The co-transiting system consists of a super-Earth, warm Jupiter, and massive companion at 5.8, 53, and 2900 day orbital periods, respectively. We perform dynamical simulations to study the past and future of the system. von-Zeipel-Kozai-Lidov oscillations emerge as the most plausible scenario to explain the outer companion's high orbital eccentricity, with planet-planet scattering a possible but less likely contender. Due to non-zero mutual inclinations between the planets, the system is visibly evolving on very short timescales, with the current co-transiting configuration ending in 200 years.