Periodic Table of Exoplanets (IMAGE) University of Puerto Rico, Arecibo Campus Caption Scientists are now starting to identify potential habitable exoplanets after nearly twenty years of the detection of the first planets around other stars. This image shows all known examples using 18 mass and temperature categories similar to a periodic table, including confirmed and unconfirmed exoplanets. Only 16 in the Terrans groups are potential habitable candidates. Credit PHL copyright UPR Arecibo Usage Restrictions Appropriate caption and credit required License Licensed content 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.