Britannica
Sources used in this answer
Why was Kepler-22b important in the search for potentially habitable planets?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
Habitable zone
The habitable zones (green) for stars that are like the Sun (middle), hotter than the Sun (top), and cooler than the Sun (bottom). The red areas are those in which liquid surface water would be lost as a result of a runaway greenhouse effect, and the blue areas are those in which liquid surface water would be completely frozen.
Kepler-22b is significant in the field of astrobiology because it was the first planet discovered within the habitable zone of a star similar to the Sun.1
The habitable zone is defined as the orbital region around a star where a planet could potentially possess liquid water on its surface, a requirement considered essential for life as we know it. While Kepler-22b has a radius 2.4 times that of Earth, its location within this critical orbital region made it a landmark discovery for the Kepler mission, which aimed to determine the frequency of planets situated at distances from their stars where liquid waterâand thus potentially lifeâcould exist.21