Habitable Zones (image) University of California - Berkeley Caption Astronomers use the term "habitable zone" to indicate an orbit not too far from the star such that water freezes, and not too close such that water vaporizes. Habitable zones are orbital areas where the heat from the star creates lukewarm temperatures at which liquid water can exist, and water is the presumed prerequisite for life. Credit Petigura/UC Berkeley, Howard/UH-Manoa, Marcy/UC Berkeley Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.