Habitable Zone

The habitable zone, also called the Goldilocks zone, is the band of orbits around a star where a planet could have liquid water on its surface — not so close that oceans boil away, not so far that they freeze.

Its location depends on how bright the star is. For the Sun, a commonly used conservative estimate is roughly 0.95 to 1.7 times Earth's distance. Around dim red dwarfs, the zone is much closer in; around bright stars, much farther out.

Being in the habitable zone does not guarantee a planet is habitable. It also needs enough mass to hold an atmosphere, and the right atmosphere to keep its temperature in range.

Try it: Habitable zone calculator · Read more in Step 2: Choosing the orbit.