Long-term orbital stability of exosolar planetary systems with highly eccentric orbits

TL;DR

This study investigates the long-term stability of exoplanetary systems with highly eccentric orbits using dynamical maps and chaos indicators, revealing that mean motion resonances can ensure stability despite Hill stability limitations.

Contribution

It demonstrates that mean motion resonances can stabilize highly eccentric exoplanetary orbits, expanding understanding of long-term planetary system dynamics.

Findings

Mean motion resonances can provide phase protection for unstable orbits.

Stable regions are associated with specific resonant conditions.

Dynamical maps identify zones of guaranteed long-term stability.

Abstract

Nowadays, many extrasolar planetary systems possessing at least one planet on a highly eccentric orbit have been discovered. In this work, we study the possible long-term stability of such systems. We consider the general three body problem as our model. Highly eccentric orbits are out of the Hill stability regions. However, mean motion resonances can provide phase protection and orbits with long-term stability exist. We construct maps of dynamical stability based on the computation of chaotic indicators and we figure out regions in phase space, where the long-term stability is guaranteed. We focus on regions where at least one planet is highly eccentric and attempt to associate them with the existence of stable periodic orbits. The values of the orbital elements, which are derived from observational data, are often given with very large deviations. Generally, phase space regions of high eccentricities are narrow and thus, our dynamical analysis may restrict considerably the valid domain of the system's location.