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This is a list of potentially habitable exoplanets. The list is mostly based on estimates of habitability by the Habitable Exoplanets Catalog (HEC), and data from the NASA Exoplanet Archive. The HEC is maintained by the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo. [1] There is also a speculative list being developed of superhabitable planets.
Surface planetary habitability is thought to require an orbit at the right distance from the host star for liquid surface water to be present, in addition to various geophysical and geodynamical aspects, atmospheric density, radiation type and intensity, and the host star's plasma environment. [2]
This is a list of exoplanets within the circumstellar habitable zone that are under 10 Earth masses and smaller than 2.5 Earth radii, and thus have a chance of being rocky. [3] [1] Note that inclusion on this list does not guarantee habitability, and in particular the larger planets are unlikely to have a rocky composition. [4] Earth is included for comparison.
Note that mass and radius values prefixed with "~" have not been measured, but are estimated from a mass-radius relationship.
Object | Star | Star type | Mass (M⊕) | Radius (R⊕) | Density (g/cm3) | Flux (F⊕) | Teq (K) | Period (days) | Distance (ly) | Refs/Notes |
---|---|---|---|---|---|---|---|---|---|---|
Earth | Sun | G2V | 1.00 | 1.00 | 5.514 | 1.00 | 255 | 365.25 | 0 | Reported for reference. Only planet known to support life. [3] |
Venus | Sun | G2V | 0.815 | 0.9499 | 5.243 | 1.911 | 244.261 | 224.7 | 0 | Reported for reference. [5] |
Gliese 163 c | Gliese 163 | M3V | ≥6.80 | — | — | 1.25 | 277 | 25.6 | 49 | [1] |
Gliese 180 c | Gliese 180 | M2V | ≥6.40 | — | — | 0.78 | 239 | 24.3 | 39 | Not confirmed [1] [6] |
Gliese 180 d | Gliese 180 | M2V | ≥7.56 | — | — | 0.26 | 106.3 | 39 | [1] | |
Gliese 229 Ac | Gliese 229 A | M1V | ≥8.57 | — | — | 0.44 | 216 | 121.9 | 18.8 | |
Gliese 357 d | Gliese 357 | M2V | ≥6.10 | — | — | 0.38 | 200 | 55.7 | 31 | |
Gliese 433 d | Gliese 433 | M2V | ≥5.22 | — | — | 1.06 | 36.1 | 29.6 | [1] | |
Gliese 514 b | Gliese 514 | M1V | ≥5.20 | — | — | 0.28 (0.114−0.79) | 202 | 140.4 | 25 | Highly eccentric [7] |
Gliese 625 b | Gliese 625 | M2V | ≥2.82 | — | — | 14.628 | 21.1 | Only in HZ if very optimistic models used [8] [9] [10] | ||
Gliese 667 Cc | Gliese 667 C | M1V | ≥3.81 | ~1.54 | — | 0.88 | 277 | 28.1 | 23.62 | [11] [1] |
Gliese 1002 b | Gliese 1002 | M5V | ≥1.08 | ~1.03 | — | 0.67 | 231 | 10.3 | 15.8 | [12] |
GJ 1002 c | GJ 1002 | M5V | ≥1.36 | 1.1 | — | 0.26 | 182 | 21.2 | 15.8 | [12] [13] |
GJ 1061 c | GJ 1061 | M5V | ≥1.74 | ~1.18 | — | 1.45 | 275 | 6.7 | 12 | |
GJ 1061 d | GJ 1061 | M5V | ≥1.64 | ~1.16 | — | 0.69 | 218 | 13.0 | 12 | |
GJ 3293 d | GJ 3293 | M2V | ≥7.60 | — | — | 0.59 | 223 | 48.1 | 66 | [1] |
HD 40307 g | HD 40307 | K2V | ≥7.09 | — | — | 0.67 | 226 | 197.8 | 42 | Not confirmed [1] [14] |
HD 216520 c | HD 216520 | K0V | ≥9.44 | — | — | 1.28 | 154.4 | 64 | [1] | |
HIP 38594 b | HIP 38594 | M0V | ≥8.10 | — | — | 1.34 | 60.7 | 58 | [1] | |
K2-9b | K2-9 | M2V | — | 2.25 | — | 1.45 | 279 | 18.4 | 270 | [1] [15] |
K2-72e | K2-72 | M?V | ~2.21 | 1.29 | — | 1.30 | 261 | 24.2 | 217 | [16] |
K2-332b | K2-332 | M?V | — | 2.20 | — | 1.17 | 17.7 | 402 | [1] | |
K2-288Bb | K2-288 B | M3V | 4.27 | 1.91 | — | 0.44 | 207 | 31.4 | 214 | [17] |
Kepler-22b | Kepler-22 | G5V | — | 2.38 | — | 1.10 | 261 | 289.9 | 635 | [1] [18] |
Kepler-62e | Kepler-62 | K2V | 4.5+14.2 −2.6 | 1.61 | — | 1.15 | 264 | 122.4 | 981 | [1] [19] |
Kepler-62f | Kepler-62 | K2V | 2.8+0.4 −0.4 | 1.41 | — | 0.41 | 204 | 267.3 | 981 | [1] [20] |
Kepler-155c | Kepler-155 | M0V | — | 2.24 | — | 1.05 | 52.7 | 957 | [1] | |
Kepler-174d | Kepler-174 | K3V | — | 2.19 | — | 0.59 | 206 | 247.4 | 1254 | [1] |
Kepler-186f | Kepler-186 | M1V | 1.44+2.33 −1.12 | 1.17 | — | 0.29 | 188 | 129.9 | 579 | [1] |
Kepler-283c | Kepler-283 | K5V | — | 1.82 | — | 0.89 | 248 | 92.7 | 1526 | [1] |
Kepler-296e | Kepler-296 | K7V | 2.96 | 1.52 | — | 1.41 | 276 | 34.1 | 737 | [1] [21] [22] |
Kepler-296f | Kepler-296 | K7V | — | 1.80 | — | 0.44 | 225 | 63.3 | 737 | [1] [23] |
Kepler-442b | Kepler-442 | K5V | 2.36+5.9 −1.3 | 1.35 | — | 0.70 | 233 | 112.3 | 1193 | [1] |
Kepler-440b | Kepler-440 | K6V | — | 1.91 | — | 1.44 | 273 | 101.1 | 981 | [1] |
Kepler-443b | Kepler-443 | K3V | — | 2.35 | — | 0.89 | 247 | 177.7 | 2615 | [1] |
Kepler-443b | Kepler-443 | K3V | — | 2.35 | — | 0.89 | 247 | 177.7 | 2615 | [1] |
Kepler-452b | Kepler-452 | G2V | ~5 | 1.63 | — | 1.11 | 261 | 384.8 | 1799 | Not confirmed [1] [24] [25] [26] [27] |
Kepler-705b | Kepler-705 | M?V | — | 2.11 | — | 0.77 | 243 | 56.1 | 903 | |
Kepler-1229b | Kepler-1229 | M?V | 2.540 | 1.40 | — | 0.32 | 213 | 86.8 | 865 | [1] |
Kepler-1410b | Kepler-1410 | K?V | — | 1.78 | — | 1.07 | 274 | 60.9 | 1196 | |
Kepler-1540b | Kepler-1540 | K?V | — | 2.49 | — | 0.78 | 250 | 125.4 | 799 | |
Kepler-1544 b | Kepler-1544 | K2V | — | 1.78 | — | 0.84 | 248 | 168.8 | 1092 | [1] |
Kepler-1606b | Kepler-1606 | G?V | — | 2.07 | — | 1.64 | 277 | 196.4 | 2710 | [28] |
Kepler-1649c | Kepler-1649 | M5V | 1.20 | 1.06 | — | 0.75 | 237 | 19.5 | 301 | [29] |
Kepler-1652b | Kepler-1652 | M?V | — | 1.60 | — | 0.84 | 244 | 38.1 | 822 | |
Kepler-1653b | Kepler-1653 | K?V | — | 2.17 | — | 1.04 | 258 | 140.3 | 2461 | |
Kepler-1701b | Kepler-1701 | K?V | — | 2.22 | — | 1.42 | 275 | 169.1 | 1904 | [1] [30] |
L 98-59 f | L 98-59 | M3V | ≥2.46 | — | — | >1 | ~280 | 23.15 | 34.6 | Unconfirmed candidate [31] |
LHS 1140 b | LHS 1140 | M4V | 5.60 | 1.73 | 5.9±0.3 | 0.43 | 226 | 24.7 | 49 | Likely ocean world or dense mini-Neptune [32] |
LP 890-9 c | LP 890-9 | M6V | — | 1.37 | — | 0.91 | 272 | 8.46 | 105 | [33] |
Luyten b | Luyten's Star | M3V | ≥2.89 | ~1.35 | — | 1.06 | 258 | 18.65 | 12.3 | [34] |
Proxima Centauri b | Proxima Centauri | M5V | ≥1.27 | ~1.30 | — | 0.70 | 228 | 11.186 | 4.25 | Affected by solar flare, possibly affected by high radiation [35] |
Ross 128 b | Ross 128 | M4V | ≥1.40 | ~1.80 | — | 1.48 | 280 | 9.87 | 11.0 | [36] |
Ross 508 b | Ross 508 | M4V | ≥4.00 | — | — | 1.32 | 10.8 | 37 | [37] | |
Teegarden's Star b | Teegarden's Star | M7V | ≥1.05 | ~1.02 | — | 1.15 | 264 | 4.91 | 12.5 | Radius is estimated [38] [39] |
Teegarden's Star c | Teegarden's Star | M7V | ≥1.11 | ~1.04 | — | 0.37 | 199 | 11.4 | 12.5 | [38] |
TOI-700 d | TOI-700 | M2V | ~1.72 | 1.14 | — | 0.87 | 246 | 37.4 | 101 | |
TOI-715 b | TOI-715 | M4 | 3.02 | 1.55 | – | 0.67 | 234 | 19.29 | 137 | [40] [41] |
TOI-2257 b | TOI-2257 | M3V | 5.712+4.288 −2.311 | 2.20 | — | 0.57 (0.26−2.25) | 256+61 −17 | 35.2 | 188 | Highly eccentric [1] [42] |
TRAPPIST-1d | TRAPPIST-1 | M8V | 0.39 | 0.78 | 3.39 | 1.12 | 258 | 4.05 | 41 | Confirmed to be rocky [43] [44] |
TRAPPIST-1e | TRAPPIST-1 | M8V | 0.69 | 0.92 | 5.65 | 0.65 | 230 | 6.1 | 41 | Confirmed to be rocky [43] [44] |
TRAPPIST-1f | TRAPPIST-1 | M8V | 1.04 | 1.04 | 3.3 ± 0.9 | 0.37 | 200 | 9.2 | 41 | Confirmed to be rocky [43] [44] |
TRAPPIST-1g | TRAPPIST-1 | M8V | 1.32 | 1.13 | 4.186 | 0.25 | 182 | 12.4 | 41 | Confirmed to be rocky [43] [44] |
Wolf 1069 b | Wolf 1069 | M5V | ≥1.26 | ~1.08 | — | 0.65 | 250 | 15.6 | 31.2 | [45] |
Wolf 1061c | Wolf 1061 | M3V | ≥3.41 | ~1.60 | — | 1.30 | 271 | 17.9 | 13.8 | [1] |
Some exoplanet candidates detected by radial velocity that were originally thought to be potentially habitable were later found to most likely be artifacts of stellar activity. These include Gliese 581 d & g, [46] [47] [48] Gliese 667 Ce & f, [11] [49] Gliese 682 b & c, [6] Kapteyn b, [50] [51] and Gliese 832 c. [52]
HD 85512 b was initially estimated to be potentially habitable, [53] [54] but updated models for the boundaries of the habitable zone placed the planet interior to the HZ, [55] [56] and it is now considered non-habitable. [1] Kepler-69c has gone through a similar process; though initially estimated to be potentially habitable, [57] it was quickly realized that the planet is more likely to be similar to Venus, [58] and is thus no longer considered habitable. [1] Several other planets, such as Gliese 180 b, also appear to be examples of planets once considered potentially habitable but later found to be interior to the habitable zone. [1]
Similarly, Tau Ceti e and f were initially both considered potentially habitable, [59] but with improved models of the circumstellar habitable zone, as of 2022 PHL does not consider either planet potentially habitable. [1] [ failed verification ] Kepler-438b was also initially considered potentially habitable; however, it was later found to be a subject of powerful flares that can strip a planet of its atmosphere, so it is now considered non-habitable. [1]
K2-3d and K2-18b were originally considered potentially habitable, and the latter remains listed in the HEC, [1] but recent studies have shown them to be gaseous sub-Neptunes and thus unlikely to be habitable. [60] [61] [62] [63] [64] [65]
KOI-1686.01 was also considered a potentially habitable exoplanet after its detection in 2011, until proven a false positive by NASA in 2015. [66] Several other KOIs, like Kepler-577b and Kepler-1649b, were considered potentially habitable prior to confirmation, but with new data are no longer considered habitable.
Gliese 832 is a red dwarf of spectral type M2V in the southern constellation Grus. The apparent visual magnitude of 8.66 means that it is too faint to be seen with the naked eye. It is located relatively close to the Sun, at a distance of 16.2 light years and has a high proper motion of 818.16 milliarcseconds per year. Gliese 832 has just under half the mass and radius of the Sun. Its estimated rotation period is a relatively leisurely 46 days. The star is roughly 6 billion years old.
An exoplanet is a planet located outside the Solar System. The first evidence of an exoplanet was noted as early as 1917, but was not recognized as such until 2016; no planet discovery has yet come from that evidence. What turned out to be the first detection of an exoplanet was published among a list of possible candidates in 1988, though not confirmed until 2003. The first confirmed detection came in 1992, with the discovery of terrestrial-mass planets orbiting the pulsar PSR B1257+12. The first confirmation of an exoplanet orbiting a main-sequence star was made in 1995, when a giant planet was found in a four-day orbit around the nearby star 51 Pegasi. Some exoplanets have been imaged directly by telescopes, but the vast majority have been detected through indirect methods, such as the transit method and the radial-velocity method. As of 1 May 2024, there are 5,662 confirmed exoplanets in 4,169 planetary systems, with 896 systems having more than one planet. This is a list of the most notable discoveries.
K2-3, also known as EPIC 201367065, is a red dwarf star with three known planets. It is on the borderline of being a late orange dwarf/K-type star, but because of its temperature, it is classified as a red dwarf.
GJ 625 is a small red dwarf star with an exoplanetary companion in the northern constellation of Draco. The system is located at a distance of 21.1 light-years from the Sun based on parallax, but is drifting closer with a radial velocity of −13 km/s. It is too faint to be visible to the naked eye, having an apparent visual magnitude of 10.13 and an absolute magnitude of 11.06.
GJ 3470 b is an exoplanet orbiting the star GJ 3470, located in the constellation Cancer. With a mass of just under 14 Earth-masses and a radius approximately 4.3 times that of Earth's, it is likely something akin to Neptune despite the initially strong belief that the planet was not covered in clouds like the gas giants in the Solar System.
GJ 9827 is a star in the constellation of Pisces. It is a K-type main-sequence star with an apparent magnitude of 10.250. It is 97 light-years away, based on parallax.
GJ 357 is an M-type main sequence star with an unusually low starspot activity. It is located 31 light-years from the Solar System. The system is part of the Hydra constellation.
K2-18, also known as EPIC 201912552, is a red dwarf star with two planetary companions located 124 light-years from Earth, in the constellation of Leo.
GJ 3470 is a red dwarf star located in the constellation of Cancer, 96 light-years away from Earth. With a faint apparent magnitude of 12.3, it is not visible to the naked eye. It hosts one known exoplanet.
Kepler-1649 is a red dwarf star of spectral type M5V with a radius 0.232 R☉, a mass 0.198 M☉, and a metallicity of -0.15 [Fe/H].