The Habitable Exoplanets Catalog (HEC) list a selection of all known exoplanets with any potential to support life, including some unconfirmed planets. The catalog tries to be as open as possible as not to exclude any object of interest. This selection can be narrowed down as desired using more conservative criteria based on different habitability metrics. For example, the following two figures divides the objects of interest of HEC into a conservative and optimistic sample.

This is the selection of planets that match the Conservative Definition of a Potentially Habitable Exoplanet. These planets are more likely to be of rocky composition and with the right temperatures for liquid water. Image Credit: PHL @ UPR Arecibo.

This is the selection of planets that match the Optimistic Definition of a Potentially Habitable Exoplanet. These planets are less likely to be of rocky composition or with the right temperatures for liquid water. Image Credit: PHL @ UPR Arecibo.

Location in the night sky of all the known stellar systems with potentially habitable worlds (some systems have more than one). Click the image to enlarge. Image Credit: PHL @ UPR Arecibo, Jim Cornmell.