HEC: Periodic Table of Exoplanets

Last Update: July 23, 2014

The Periodic Table of Exoplanets divides most of the known exoplanets into six mass/size and three temperatures groups for visualization purposes (18 categories total). Exoplanets in the Hot Zone are too close of their parent star to have liquid water. Those in the Warm 'Habitable' Zone have the right distance for liquid water given the right size and atmosphere. Water can only exist as ice for those in the Cold Zone. Miniterrans are low mass bodies most likely spherical and without atmospheres, similar to Mercury and the Moon. Subterrans are comparable to Mars, Terrans to Earth and Venus, and Superterrans are a transition group between terrans and neptunians. Neptunians are similar in mass to Neptune and Uranus, and Jovians to Jupiter and Saturn, or larger. Not all bodies stated in the objects count in the title are classified in the table due to unknown stellar or planetary parameters. Those potentially habitable are described with more details in the Habitable Exoplanet Catalog (HEC).


Figure 1. Current confirmed exoplanets classified into eighteen thermal-mass categories. The number of exoplanets in each category is shown in the center of each frame and as a percent in the lower left. The diagram also shows the number of multiple stellar systems (top right). The most abundant objects of the confirmed exoplanets are hot jovians. RE = Earth radii, ME = Earth masses. CREDIT: PHL @ UPR Arecibo.



Figure 2. Current NASA Kepler exoplanets candidates classified into eighteen thermal-size categories. The number of exoplanets in each category is shown in the center of each frame and as a percent in the lower left. The number of those already confirmed are shown in the lower right. The diagram also shows the number of multiple stellar systems (top right). The most abundant objects of the Kepler exoplanets are hot terran and superterrans. RE = Earth radii. CREDIT: PHL @ UPR Arecibo.



Figure 3.
 Current Solar System spherical objects (with mass over 10-5 Earth masses) including planets, dwarf-planets, and moons classified into eighteen thermal-mass categories. The number of objects in each category is shown in the center of each frame and as a percent in the lower left. The diagram helps as a base for comparison with the tables for exoplanets (figure 1 and 2). The most abundant objects of the Solar System are cold miniterrans (dwarf-planets and moons). RE = Earth radii, ME = Earth masses. CREDIT: PHL @ UPR Arecibo.


Figure 4. Simple summary of the number of confirmed exoplanets in each planet category. CREDIT: PHL @ UPR Arecibo.