Thursday, April 30, 2015 @ 10:00 AM AST: First Earth-like Worlds Workshop

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These are artistic representations of all the planets around other stars (exoplanets) with any potential to support surface life as we know itMost of them are larger than Earth and we are not certain about their composition and habitability. They are ranked here from closest to farthest from Earth. This selection of objects of interest is subject to change as new interpretations or astronomical observations are made. Earth, Mars, Jupiter, and Neptune are shown for scale on the right.


Current Number of Potentially Habitable Exoplanets
Subterran
(Mars-size)

Terran
(Earth-size)
Superterran
(Super-Earth)
Total
0 10 20 30

subterran0.1 — 0.5 ME or 0.4 — 0.8 RE, terran0.5 — 5 ME or 0.8 — 1.5 RE, superterran5 — 10 ME or 1.5 — 2.5 REME = Earth masses, and RE = Earth radii.
Name Type Mass
(ME)
Radius
(RE)
Flux
(FE)
Teq
(K)
Period
(days)
Distance
(ly)
ESI
001. Kepler-438 b K-Warm Terran 4.0 - 1.3 - 0.6 1.1 1.38 276 35.2 473 0.88
002. Kepler-296 e M-Warm Terran 12.5 - 3.3 - 1.4 1.5 1.22 267 34.1 1692 0.85
003. GJ 667C c M-Warm Terran 3.8 1.1 - 1.5 - 2.0 0.88 247 28.1 24 0.84
004. Kepler-442 b K-Warm Terran 8.2 - 2.3 - 1.0 1.3 0.70 233 112.3 1115 0.84
005. Kepler-62 e K-Warm Superterran 18.7 - 4.5 - 1.9 1.6 1.10 261 122.4 1200 0.83
006. GJ 832 c M-Warm Superterran 5.4 1.2 - 1.7 - 2.2 1.00 253 35.7 16 0.81
007. EPIC 201367065 d M-Warm Superterran 14.1 - 3.7 - 1.5 1.5 1.51 282 44.6 147 0.80
008. Kepler-283 c K-Warm Superterran 35.3 - 7.0 - 2.8 1.8 0.90 248 92.7 1741 0.79
009. tau Cet e* G-Warm Terran 4.3 1.1 - 1.6 - 2.0 1.51 282 168.1 12 0.78
010. GJ 180 c* M-Warm Superterran 6.4 1.3 - 1.8 - 2.3 0.79 239 24.3 38 0.77
011. GJ 667C f* M-Warm Terran 2.7 1.0 - 1.4 - 1.8 0.56 221 39.0 24 0.77
012. Kepler-440 b K-Warm Superterran 41.2 - 7.7 - 3.1 1.9 1.43 273 101.1 851 0.75
013. GJ 180 b* M-Warm Superterran 8.3 1.3 - 1.9 - 2.4 1.23 268 17.4 38 0.75
014. GJ 163 c M-Warm Superterran 7.3 1.3 - 1.8 - 2.4 1.40 277 25.6 49 0.75
015. HD 40307 g K-Warm Superterran 7.1 1.3 - 1.8 - 2.3 0.68 227 197.8 42 0.74
016. EPIC 201912552 b (N) M-Warm Superterran N/A - 16.5 - 6.0 2.2 0.94 251 32.9 111 0.73
017. Kepler-61 b K-Warm Superterran N/A - 13.8 - 5.2 2.2 1.27 267 59.9 1063 0.73
018. Kepler-443 b K-Warm Superterran N/A - 19.5 - 7.0 2.3 0.89 247 177.7 2540 0.71
019. Kepler-22 b G-Warm Superterran N/A - 20.4 - 7.2 2.4 1.11 261 289.9 619 0.71
020. GJ 422 b* M-Warm Superterran 9.9 1.4 - 2.0 - 2.6 0.68 231 26.2 41 0.71
021. GJ 3293 c* M-Warm Superterran 8.6 1.4 - 1.9 - 2.5 0.60 223 48.1 59 0.70
022. Kepler-298 d K-Warm Superterran N/A - 26.8 - 9.1 2.5 1.29 271 77.5 1545 0.68
023. Kapteyn b M-Warm Terran 4.8 1.2 - 1.6 - 2.1 0.43 205 48.6 13 0.67
024. Kepler-62 f K-Warm Terran 10.2 - 2.8 - 1.2 1.4 0.39 201 267.3 1200 0.67
025. Kepler-174 d K-Warm Superterran N/A - 14.8 - 5.5 2.2 0.43 206 247.4 1174 0.61
026. Kepler-186 f M-Warm Terran 4.7 - 1.5 - 0.6 1.2 0.29 188 129.9 561 0.61
027. GJ 667C e* M-Warm Terran 2.7 1.0 - 1.4 - 1.8 0.30 189 62.2 24 0.60
028. Kepler-296 f M-Warm Superterran 28.7 - 6.1 - 2.5 1.8 0.34 194 63.3 1692 0.60
029. GJ 682 c* M-Warm Superterran 8.7 1.4 - 1.9 - 2.5 0.37 198 57.3 17 0.59
030. KOI-4427 b* K-Warm Superterran 38.5 - 7.4 - 3.0 1.8 0.24 179 147.7 782 0.52

* planet canditate/unconfirmed, (N) = new addition to the catalog
















Table Legend


  • Name - Name of the planet. This links to the data of the planet at the Extrasolar Planets Encyclopaedia or 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 - Minimum mass of the planet in Earth masses (Earth = 1.0 ME). Estimated for a pure iron, rocky, and water composition, respectively, when not available. 
  • Radius - Radius of planet in Earth radii (Earth = 1.0 RE). Estimated for a pure iron, rocky, and water composition, respectively, when not available.
  • Flux - Average stellar flux of the planet in Earth fluxes (Earth = 1.0 FE).
  • Teq - Equilibrium temperature in kelvins (K) assuming a 0.3 bond albedo (Earth = 255 K). Actual surface temperatures are expected to be larger than the equilibrium temperature depending on the atmosphere of the planets, which are currently unknown (e.g. Earth mean global surface temperature is about 288 K or 15°C).
  • 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 that compares how similar are these planets to the stellar flux, mass, and radius of Earth (Earth = 1.0). Results are sorted by this number.


The figure above shows all planets near the habitable zone (green shades). Only those less than 10 Earth masses or 2.5 Earth radii are labeled. Some are still unconfirmed (* = unconfirmed). 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).