The role of dynamics on the habitability of an Earth-like planet

TL;DR

This paper investigates how the orbital dynamics and inclinations of giant planets like Jupiter and Saturn influence the stability and habitability of Earth-like planets within the habitable zone, highlighting the importance of planetary system architecture.

Contribution

It provides a numerical analysis of how giant planet configurations affect the orbital stability and habitability potential of terrestrial planets, emphasizing the role of planetary inclinations.

Findings

Strong gravitational perturbations can be mitigated by neighboring planets.

Moderate inclinations can reduce perturbations in the habitable zone.

Earth-like planets maintain low eccentricity orbits when Saturn's inclination is <=10°.

Abstract

From the numerous detected planets outside the Solar system, no terrestrial planet comparable to our Earth has been discovered so far. The search for an Exo-Earth is certainly a big challenge which may require the detections of planetary systems resembling our Solar system in order to find life like on Earth. However, even if we find Solar system analogues, it is not certain that a planet in Earth position will have similar circumstances as those of Earth. Small changes in the architecture of the giant planets can lead to orbital perturbations which may change the conditions of habitability for a terrestrial planet in the habitable zone (HZ). We present a numerical investigation where we first study the motion of test-planets in a particular Jupiter-Saturn configuration for which we can expect strong gravitational perturbations on the motion at Earth position according to a previous work. In this study, we show that these strong perturbations can be reduced significantly by the neighboring planets of Earth. In the second part of our study we investigate the motion of test-planets in inclined Jupiter-Saturn systems where we analyze changes in the dynamical behavior of the inner planetary system. Moderate values of inclination seem to counteract the perturbations in the HZ while high inclinations induce more chaos in this region. Finally, we carry out a stability study of the actual orbits of Venus, Earth and Mars moving in the inclined Jupiter-Saturn systems for which we used the Solar system parameters. This study shows that the three terrestrial planets will only move in low-eccentric orbits if Saturn's inclination is <=10{\deg}. Therefore, it seems that it is advantageous for the habitability of Earth when all planets move nearly in the same plane.