List of nearest terrestrial exoplanet candidates

This list of nearest space terrestrial exoplanets candidates contains possible terrestrial ("rocky") exoplanets space at a distance of up to 50 light-years from the Solar System, ordered by increasing distance.[1][2][3]

They may be composed primarily of silicate rocks and/or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun.

Incompleteness of the list

This list is incomplete, currently containing 33 exoplanets, 11 of which probably lie inside their star's habitable zone.

There are roughly 2,000 stars at a distance of up to 50 light-years from the Solar System[4] (64 of them are yellow-orange "G" stars like our Sun[5]). As many as 15% of them can have Earth-sized planets in the habitable zones.[6]

On November 4, 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of sun-like stars and red dwarf stars within the Milky Way Galaxy.[7][8] 11 billion of these estimated planets may be orbiting sun-like stars.[9] The nearest such planet may be 12 light-years away, according to the scientists.[7][8]

On August 24, 2016, astronomers announced the discovery of a rocky planet in the habitable zone of Proxima Centauri, the closest star to Earth. Called Proxima b, the planet is 1.3 times the mass of Earth and has an orbital period of roughly 11.2 Earth days.[10] However Proxima Centauri’s classification as a red dwarf casts doubts on the habitability of any exoplanets in its orbit due to low stellar flux, high probability of tidal locking, small circumstellar habitable zones and high stellar variation. Another likely candidate is Alpha Centauri, Earth’s nearest Sun-like star system 4.37 light years away. Estimates place the probability of finding a habitable planet around Alpha Centauri A or B at roughly 85%.[11] Alpha Centauri is the target of several exoplanet-finding missions, including Breakthrough Starshot and Mission Centaur, the latter of which is chronicled in the 2016 documentary film, "The Search for Earth Proxima."[12]

Table

Name Image
(art. concept)
M R g Ts a e [s] D
Proxima Centauri b
≥1.27 ~1.1 234 K
-39°C
0.05<0.35 [13]4.22
Wolf 1061b ≥1.36≥1.44 13.8
Wolf 1061c ≥4.3≥1.64 [14] 13.8
Wolf 1061d ≥5.21≥2.04 13.8
Gliese 876 d[15]
6.8 650 K
377 °C[16]
0.0210.21[17]15
Gliese 682 b ≥2 [6]
[18]
[14]
16
Gliese 832 c
≥5.4 295 K
22 °C
0.162 0.03 [19][20]16.16
82 G. Eridani b ≥2.7 660 K
387 °C[1]
0.1207 0[2]19.71
82 G. Eridani c ≥2.4 508 K
235 °C[1]
0.2036 0 [2]19.71
82 G. Eridani d ≥4.8 388 K
115 °C[1]
0.3499 0[2]19.71
Gliese 581 e
≥1.7 0.0290[21]20
Gliese 581 c [22]
≥5.6 0.0720[21]20
Gliese 581 d [23]
≥5.6 2.34[24] 1.27[24]233 K
-41 °C[24]
0.2180[21]20
HD 219134 b
4.5 1.6 700 K
427 °C
[25] 21
Gliese 667C b
6.30 1.44 445 K

172 °C

0.05 0.09 [24] 22
Gliese 667C c[26][27]
3.8 1.32 302 K
29 °C
0.13 0.34 [24] 22
61 Virginis b[28]
≥5.1 0.0500.12[29]28
HD 85512 b[30]
≥3.6 1.74[24] 1.33[24] 351 K
78 °C[24]
0.260.11[31]36
GJ 180 b ≥2.3 312 K
39 °C
[6][19] 38
TRAPPIST-1b
[32]39.5
TRAPPIST-1c
[32]39.5
TRAPPIST-1d
[32]39.5
TRAPPIST-1e
[32]39.5
TRAPPIST-1f
[32]39.5
TRAPPIST-1g
[32]39.5
TRAPPIST-1h
[32]39.5
55 Cancri e (Janssen)
8.6 0.0160.17[33]40
HD 40307 b[34]
≥4.2 0.0470.2[34]42
HD 40307 c[34]
≥6.8 0.0810.06[34]42
HD 40307 d [35]
≥9.2 0.1340.07[34]42
HD 40307 e ≥3.5 0.1886 0.15 [3]42
HD 40307 f ≥5.2 385 K
112 °C
0.247 0.02 [3]42
HD 40307 g ≥7.1 284 K
11 °C[36]
0.600 0.29[3]42

Note: There is no scientific consensus about terrestrial composition of most of the planets in the list. Sources in the "Main source" column confirm the possibility of terrestrial composition.

In September 2012, the discovery of two planets orbiting Gliese 163[37] was announced.[38][39] One of the planets, Gliese 163 c, about 6.9 times the mass of Earth and somewhat hotter, was considered to be within the habitable zone, but is probably not terrestrial.[38][39] In May 2016, the finding of three earth-like planets of ultracool dwarf TRAPPIST-1 has been released.

Statistics

Distance from the Solar System
Distance Lying within
the habitable zone
All
< 10 light-years 0 2
< 20 light-years 6 15
< 30 light-years 8 22
< 40 light-years 10 24
< 50 light-years 11 31

Note: in most cases the composition of the atmosphere and atmosphere pressure of exoplanets are unknown, so surface temperatures are estimates based on computer models and expert opinions.

See also

References

  1. 1 2 3 4 Pepe, F.; et al. (2011), "The HARPS search for Earth-like planets in the habitable zone: I – Very low-mass planets around HD20794, HD85512 and HD192310", Astronomy & Astrophysics, 534: A58, Bibcode:2011A&A...534A..58P, arXiv:1108.3447Freely accessible, doi:10.1051/0004-6361/201117055
  2. 1 2 3 4 Schneider, Jean, "Star: HD 20794", Extrasolar Planets Encyclopaedia, Paris Observatory, retrieved 2011-12-05
  3. 1 2 3 4 Tuomi, Anglada-Escude, Gerlach, Jones, Reiners, Rivera, Vogt, Butler, Mikko, Guillem, Enrico, Hugh R. R., Ansgar, Eugenio J., Steven S., R. Paul; Anglada-Escude, Guillem; Gerlach, Enrico; Jones, Hugh R. R.; Reiners, Ansgar; Rivera, Eugenio J.; Vogt, Steven S.; Paul Butler, R. (2012). "Habitable-zone super-Earth candidate in a six-planet system around the K2.5V star HD 40307". Astronomy & Astrophysics. 549: A48. Bibcode:2013A&A...549A..48T. arXiv:1211.1617v1Freely accessible. doi:10.1051/0004-6361/201220268.
  4. "Stars within 50 light years". Retrieved 3 October 2015.
  5. "G stars within 100 light-years". Retrieved 3 October 2015.
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  7. 1 2 Overbye, Dennis (November 4, 2013). "Far-Off Planets Like the Earth Dot the Galaxy". New York Times. Retrieved November 5, 2013.
  8. 1 2 Petigura, Eric A.; Howard, Andrew W.; Marcy, Geoffrey W. (October 31, 2013). "Prevalence of Earth-size planets orbiting Sun-like stars". Proceedings of the National Academy of Sciences of the United States of America. 110 (48): 19273–19278. Bibcode:2013PNAS..11019273P. PMC 3845182Freely accessible. PMID 24191033. arXiv:1311.6806Freely accessible. doi:10.1073/pnas.1319909110. Retrieved November 5, 2013.
  9. Khan, Amina (November 4, 2013). "Milky Way may host billions of Earth-size planets". Los Angeles Times. Retrieved November 5, 2013.
  10. Anglada-Escudé, Guillem (August 24, 2016). "A terrestrial planet candidate in a temperate orbit around Proxima Centauri" (PDF). Nature. 536: 437–40. PMID 27558064. doi:10.1038/nature19106.
  11. Billings, Lee. "Miniature Space Telescope Could Boost the Hunt for "Earth Proxima"". Scientific American.
  12. "The Search for Earth Proxima". The Atlantic.
  13. Anglada-Escudé, Guillem; Amado, Pedro J.; Barnes, John; Berdiñas, Zaira M.; Butler, R. Paul; Coleman, Gavin A. L.; de la Cueva, Ignacio; Dreizler, Stefan; Endl, Michael; Giesers, Benjamin; Jeffers, Sandra V.; Jenkins, James S.; Jones, Hugh R. A.; Kiraga, Marcin; Kürster, Martin; López-González, Marίa J.; Marvin, Christopher J.; Morales, Nicolás; Morin, Julien; Nelson, Richard P.; Ortiz, José L.; Ofir, Aviv; Paardekooper, Sijme-Jan; Reiners, Ansgar; Rodríguez, Eloy; Rodrίguez-López, Cristina; Sarmiento, Luis F.; Strachan, John P.; Tsapras, Yiannis; Tuomi, Mikko; Zechmeister, Mathias (25 August 2016). "A terrestrial planet candidate in a temperate orbit around Proxima Centauri". Nature. 536 (7617): 437–440. ISSN 0028-0836. PMID 27558064. arXiv:1609.03449Freely accessible. doi:10.1038/nature19106.
  14. 1 2 http://phl.upr.edu/projects/habitable-exoplanets-catalog/data
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  16. Rivera, E.; et al. (2005). "A ~7.5 M⊕ Planet Orbiting the Nearby Star, GJ 876". The Astrophysical Journal. 634 (1): 625–640. Bibcode:2005ApJ...634..625R. doi:10.1086/491669.
  17. Eugenio J. Rivera, Gregory Laughlin, R. Paul Butler, Steven S. Vogt, Nader Haghighipour, Stefano Meschiari (2010). "The Lick-Carnegie Exoplanet Survey: A Uranus-mass Fourth Planet for GJ 876 in an Extrasolar Laplace Configuration".
  18. http://www.hpcf.upr.edu/~abel/phl/tuomi/hec_orbit_GJ_682_b.png
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  24. 1 2 3 4 5 6 7 8 The Habitable Exoplanets Catalog. The values are just the best estimates and are subject to change.
  25. http://phys.org/news/2015-07-astronomers-star-super-earths.html
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  37. Staff (September 20, 2012). "LHS 188 -- High proper-motion Star". Centre de données astronomiques de Strasbourg(Strasbourg astronomical Data Center). Retrieved September 20, 2012.
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