Planetary Habitability Lab / UPR This "periodic table" of
exoplanets, including confirmed planets as well as candidates
from NASA's Kepler mission, places exoplanets into 18 categories
based on mass and temperature. The numbers keep track of how
many worlds are in which categories. Click on the image to see a
larger, more readable version. Researchers have set up an online
"periodic table" for extrasolar planets ranging from Hot
Mercurians to Cold Jovians, with Earthlike worlds right in the
middle. The Habitable Exoplanets Catalog, drawn up by the
University of Puerto Rico's Planetary Habitability Laboratory,
is aimed at pigeonholing the hundreds of worlds that are being
identified by NASA's Kepler space telescope and other planet-
hunting projects. Eventually, the tally of exoplanets is
expected to mount into the thousands, and that's where
researchers hope the proposed catalog will come in handy. "One
important outcome of these rankings is the ability to compare
exoplanets from best to worst candidates for l