Finding Earth 2.0
A data-driven lens on orbital eccentricity and planetary habitability.
Eccentric orbits matter because they can make a planet’s climate less stable over time, which can reduce the long-term prospects for liquid water and sustained surface habitability.
Background & context
In a nearly circular orbit, a planet receives a comparatively steady flux of stellar energy, so seasonal forcing is modest. In an eccentric orbit, the planet moves closer to and farther from its host star over the course of the year, and the incoming flux can vary substantially.
In a simple orbital approximation, the time-averaged flux scales roughly as \(F \propto \frac{L_\star}{a^2\sqrt{1-e^2}}\), so even moderate eccentricity can amplify seasonal and climatic variability. For habitability studies, that matters because large swings in temperature and water availability can make long-term surface stability more difficult to maintain.
Study goals
Outcome variable
The outcome is a binary indicator of orbital eccentricity:
- Eccentric orbit:
pl_orbeccen >= 0.1 - Circular orbit:
pl_orbeccen < 0.1
Modeling goal
Determine if exoplanet orbital eccentricity can be accurately modeled using only fundamental star system properties.
Covariates used in the model
st_met (stellar metallicity)
Tracks the abundance of elements heavier than hydrogen and helium.
st_mass (stellar mass)
Represents the host star’s mass and gravitational scale.
st_teff (stellar effective temperature)
Captures the star’s radiative environment.
st_logg (stellar surface gravity)
Measures how strongly the stellar photosphere is bound, reflecting stellar structure.
sy_pnum (number of planets in system)
Represents system multiplicity and potential for dynamical interactions.