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Your guide to exoplanet habitability

(for life as we know it)

PLANETS

Orbits

How and where a planet orbits its star is very important for its habitability.

Habitable planets are likely found in the Goldilocks zone, meaning they’re just the right distance from their star where liquid water may exist on the surface.

Planets in eccentric orbits — or those experiencing dramatic changes in tilt — could have extreme seasons.

Planets which orbit too closely to each other can affect the stability of each other’s orbits and climates.

Magnetic Fields

On Earth, magnetic fields are produced by a spinning molten iron core.

The field protects the planet’s atmosphere from harmful activity from its star, which could impact the habitability for some forms of life.

Planet Size

The size of a planet plays a large role in how much atmosphere it can hold.

Planets that are too large hide their surfaces under atmospheres much thicker than Earth’s.

Small planets can’t keep their stars’ stellar winds from blowing away their atmospheres.

Composition

A planet must include the elements needed for life.

Water, especially liquid water, is considered the key component for life.

Radioactive elements help drive life-supporting processes like plate tectonics and magnetic field formation.

But too much of them could disrupt the planet’s chemistry, climate or plate tectonics. 

SOURCES

Based on “Impact of Space Weather on Climate and Habitability of Terrestrial Type of Exoplanets,” Airapetian et al. (2019). Specific contributions from Ravi Kumar Kopparapu, Wade Henning and Joshua Schlieder.