Effects of variable eccentricity on the climate of an Earth-like world

TL;DR

This study uses advanced climate modeling to explore how variable orbital eccentricity and the presence of a nearby Jupiter-like planet affect the climate and potential habitability of Earth-like exoplanets.

Contribution

It presents the first 3-D GCM simulations with a fully-coupled ocean and evolving orbital eccentricity influenced by a giant planet.

Findings

Earth-like planets can maintain temperate climates despite eccentricity variations.

Proximity of gas giants may enhance habitability of exoplanets.

Eccentricity evolution over thousands of years does not necessarily lead to uninhabitable conditions.

Abstract

The Kepler era of exoplanetary discovery has presented the Astronomical community with a cornucopia of planetary systems very different from the one which we inhabit. It has long been known that Jupiter plays a major role in the orbital parameters of Mars and it's climate, but there is also a long-standing belief that Jupiter would play a similar role for Earth if not for its large moon. Using a three dimensional general circulation model (3-D GCM) with a fully-coupled ocean we simulate what would happen to the climate of an Earth-like world if Mars did not exist, but a Jupiter-like planet was much closer to Earth's orbit. We investigate two scenarios that involve evolution of the Earth-like planet's orbital eccentricity from 0--0.283 over 6500 years, and from 0--0.066 on a time scale of 4500 years. In both cases we discover that they would maintain relatively temperate climates over the time-scales simulated. More Earth-like planets in multi-planet systems will be discovered as we continue to survey the skies and the results herein show that the proximity of large gas giant planets may play an important role in the habitability of these worlds. These are the first such 3-D GCM simulations using a fully-coupled ocean with a planetary orbit that evolves over time due to the presence of a giant planet.