Stability analysis of the Martian obliquity during the Noachian era

TL;DR

This study uses numerical simulations to analyze the stability of Mars's obliquity during the Noachian era, revealing two main stable zones at low and high obliquities with oscillations under 20 degrees.

Contribution

It identifies stable obliquity zones for Mars during the Noachian era under different primordial planetary configurations.

Findings

Two large stable obliquity zones below 30° and above 60°.

Oscillation amplitudes in these zones are less than 20°.

Intermediate obliquities exhibit resonant or chaotic behavior.

Abstract

We performed numerical simulations of the obliquity evolution of Mars during the Noachian era, at which time the giant planets were on drastically different orbits than today. For the preferred primordial configuration of the planets we find that there are two large zones where the Martian obliquity is stable and oscillates with an amplitude lower than 20$^\circ$. These zones occur at obliquities below 30$^\circ$ and above 60$^\circ$; intermediate values show either resonant or chaotic behaviour depending on the primordial orbits of the terrestrial planets.