What makes a planet habitable?

Whether a planet is habitable — or can host life — depends on a complex network of interactions among the planet, other planets in its solar system, and the star they orbit. The standard definition for a habitable planet is one that can sustain life for a significant period; based on our solar system, life requires liquid water, energy, and nutrients. A “habitable zone” is the region around a star where planets can receive the perfect amount of heat to maintain liquid water on their surfaces. Because Earth is in the habitable zone of the Sun, this arrangement has informed our understanding of habitability. However, as researchers discover unexpected environments that can sustain life, the requirements for habitability on exoplanets are being redefined. We’re learning that even in the habitable zone, planets may not be habitable. Planets orbiting stars that produce high levels of X-ray and UV flux from flares and activity could end up stripped of their atmosphere, leading to a planet that may be warm but completely airless. SEEC scientists are designing cutting-edge models to understand the range of planetary environments that could support life and generate detectable biosignatures.