The Habitable Exoplanets Catalog

Last Update: December 6, 2021

The Habitable Exoplanets Catalog is a database of potentially habitable worlds discovered by ground and space telescopes in the last decade. The exoplanet data comes from the NASA Exoplanet Archive and includes planets up to 2.5 Earth radii or 10 Earth masses orbiting within the optimistic stellar habitable zone to be as inclusive as possible. A more conservative sample includes planets up to 1.6 Earth radii or 3 Earth masses and thus more likely to be rocky.

subterran = 0.1 — 0.5 ME or 0.4 — 0.8 RE, terran = 0.5 — 3 ME or 0.8 — 1.6 RE, superterran = 3 — 10 ME or 1.6 — 2.5 RE. ME = Earth masses, and RE = Earth radii.

Conservative Sample of Potentially Habitable Exoplanets

This is a list of the exoplanets that are more likely to have a rocky composition and maintain surface liquid water (i.e., 0.5 < Planet Radius ≤ 1.6 Earth radii or 0.1 < Planet Minimum Mass ≤ 3 Earth masses). They are represented artistically in the top image.

Optimistic Sample of Potentially Habitable Exoplanets

This is a list of the exoplanets that are less likely to have a rocky composition or maintain surface liquid water (i.e. 1.6 < Planet Radius ≤ 2.5 Earth radii or 3 < Planet Minimum Mass ≤ 10 Earth masses). Some of these planets might turn out to be ocean worlds or mini-Neptunes.

Tables Legend

  • Name - Name of the planet. This links to the data of the planet at the NASA Exoplanet Archive.

  • Type - PHL's classification of planets that includes host star spectral type (F, G, K, M), habitable zone location (hot, warm, cold), and size (miniterran, subterran, terran, superterran, jovian, neptunian) (e.g., Earth = G-Warm Terran, Venus = G-Hot Terran, Mars = G-Warm Subterran).

  • Mass - Mass of the planet in Earth masses (Earth = 1.0 ME). Mass was estimated (~) from radius when not available using Chen & Kipping (2017). Usually, we only know the minimum (≥) mass.

  • Radius - Radius of planet in Earth radii (Earth = 1.0 RE). Radius was estimated (~) from mass when not available using Chen & Kipping (2017).

  • Flux - Average stellar flux of the planet in Earth fluxes (Earth = 1.0 SE).

  • Tsurf - Estimated (~) surface temperature in Kelvins (K) assuming an Earth-like atmosphere (i.e. same bond albedo and greenhouse) using Méndez & Rivera-Valentín (2017). Temperatures could be much larger for thicker atmospheres (Earth = 288 K).

  • Period - Orbital period in days (Earth = 365 days).

  • Distance - Distance from Earth in light-years (ly).

  • ESI - Earth Similarity Index, a measure of similarity to Earth's stellar flux, and mass or radius (Earth = 1.0). Results are sorted by this number. Planets more similar to Earth are not necessarily more habitable, since the ESI does not consider all factors necessary for life.

  • (N) = new in 2021

Habitable Zone Plot

The figure above shows all planets near the habitable zone (darker green shade is the conservative habitable zone and the lighter green shade is the optimistic habitable zone). Only those planets less than 10 Earth masses or 2.5 Earth radii are labeled. The different limits of the habitable zone are described in Kopparapu et al. (2014). Size of the circles corresponds to the radius of the planets (estimated from a mass-radius relationship when not available). Larger version here. Credit: PHL @ UPR Arecibo.

Stellar Map

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

Stellar System Plots (Conservative Sample)

Acknowledgments

This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program.

This research is partially supported by the High Performance Computing Facility (HPCf), the University of Puerto Rico, the Puerto Rico INBRE grant P20 RR-016470 from the National Center for Research Resources (NCRR), a component of the National Institutes of Health (NIH); and the Institute for Functional Nanomaterials (IFN) award 0701525 from the Experimental Program to Stimulate Competitive Research (EPSCoR) program of the National Science Foundation (NSF).