Selections from 2022: Would Changing Jupiter’s Orbit Affect Earth’s Habitability?

Editor’s Note: In these last two weeks of 2022, we’ll be looking at a few selections that we haven’t yet discussed on AAS Nova from among the most-downloaded articles published in AAS journals this year. The usual posting schedule will resume in January.

System Architecture and Planetary Obliquity: Implications for Long-term Habitability

Published September 2022

Main takeaway:

Pam Vervoort (University of California, Riverside) and collaborators used N-body simulations and climate models to study how the presence of a Jupiter-like planet affects the long-term habitability of an Earth-like planet in the same planetary system. The team’s simulations showed that if Jupiter’s orbit were more elliptical, more of Earth’s surface might be habitable than it is today.

Why it’s interesting:

With the number of confirmed exoplanets now above 5,000, many astronomers have switched from finding planets to characterizing them. Among the possible characterizations of an exoplanet is determining if it’s within its host star’s habitable zone. While the concept of the habitable zone is simple — and it’s straightforward to estimate if a planet is currently in a star’s habitable zone based on the luminosity of the star and the orbital distance of the planet — the actual location of a star’s habitable zone is expected to change over time. As stars age, their luminosity changes, and the dynamics of multi-planet systems can shift a planet’s orbital distance. Vervoort and collaborators’ simulations provide a way to estimate the impacts of some of these changes.

How a neighboring Jupiter-like planet affects habitability:

plots of simulated sea ice cover, eccentricity, obliquity, and fractional habitability for four versions of the model

Sea ice cover, eccentricity (how elliptical the orbit is), and obliquity (how tilted the planet is), and fractional habitability of an Earth-like planet in a system with a Jupiter-like planet with varying orbital parameters. Click to enlarge. [Vervoort et al. 2022]

Jupiter is often credited with helping to keep Earth habitable — by redirecting certain comets safely out of the inner solar system, for example — but is the largest planet in our solar system as helpful as it could be? Not so, say Vervoort and collaborators. The team’s simulations show that Earth’s habitability (as measured by the fraction of the planet with a hospitable air temperature and no sea ice) would be higher if Jupiter’s orbit were significantly more elliptical than it is today. While we won’t be coaxing Jupiter into a more elliptical orbit to boost Earth’s habitable area anytime soon, the results of this study can inform our investigations of potentially Earth-like planets around other stars, helping us to discern which of the growing population of exoplanets might be habitable.


Pam Vervoort et al 2022 AJ 164 130. doi:10.3847/1538-3881/ac87fd