List of nearest terrestrial exoplanet candidates

Nearest terrestrial exoplanet candidates:
- lying inside their star's habitable zone

This list of nearest terrestrial exoplanets candidates contains possible terrestrial ("rocky") exoplanets 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 26 exoplanets, 10 of which probably lie inside their star's habitable zone.

There are roughly 2000 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]

Table

Name Image
(art. concept) 		M⊕ R⊕ g Ts a e ESI Habitability [s] D
Alpha Centauri Bb
≥1.1 1200 K 0.04 Orbits too close to the star, existence not yet scientifically agreed upon 4.23
Alpha Centauri Bc 0.92±0.06 0.1 Orbits too close to the star, existence not yet scientifically agreed upon 4.23
Tau Ceti e ≥4.3 ≥1.6 343 K 0.552 ± 0.02 0.05 ± 0.02 0.77Thermoplanet Orbits on inner edge of habitable zone 11.90
Tau Ceti f ≥6.6 289–323 K 1.35 ± 0.1 0.03 ± 0.3 0.71 Mesoplanet Orbits on outer edge of habitable zone 11.90
Kapteyn b ≥5 248 K 0.68Psychroplanet. Lies within the habitable zone[10][11] 12.8
Kapteyn c ≥7 Too cold to support liquid water[11] 12.8
Wolf 1061b ≥1.36≥1.44 Too hot to support liquid water 13.8
Wolf 1061c ≥4.3≥1.64 Mesoplanet 13.8
Wolf 1061d ≥5.21≥2.04 Too cold to support liquid water 13.8
Gliese 876 d[12]
6.8 157
–
377 °C[13] 		0.0210.21 Too hot [14]15
Gliese 682 b ≥2 Thermoplanet(?).[15] Lies within the habitable zone[6]
[16] 		16
Gliese 832 c ≥5.4 295 0.162 0.03 0.81Mesoplanet. Lies within the inner edge of habitable zone [10][17]16.16
82 G. Eridani b ≥2.7 0.1207 0 Orbits too close to the star[2]19.71
82 G. Eridani c ≥2.4 0.2036 0 Orbits too close to the star [2]19.71
82 G. Eridani d ≥4.8 388 K[1] 0.3499 0 Orbits too close to the star[2]19.71
Gliese 581 e
≥1.7 0.0290 It is unlikely to possess an atmosphere due to its high temperature[18]20
Gliese 581 c [19]
≥5.6 0.0720 Questionable. Likely to lie outside the habitable zone[20][21]20
Gliese 581 d [22]
≥5.6 2.34[23] 1.27[23] 233 K[23] 0.21800.69[23]Psychroplanet.[23] Lies within the habitable zone[24][25]20
Gliese 667C b
6.30 1.44 445 K 0.05 0.09 Too hot [23] 22
Gliese 667C c[26][27]
3.8 1.32 302 K 0.13 0.34 0.82 Mesoplanet [23] 22
61 Virginis b[28]
≥5.1 0.0500.12 Orbits too close to the star[29]28
HD 85512 b[30]
≥3.6 1.74[23] 1.33[23] 351 K[23] 0.260.11 0.76[23]Thermoplanet.[23] Was considered to be the best candidate for habitability[31] until discovery of Gliese 667C c.[31]36
GJ 180 b ≥2.3 312 K 0.75Mesoplanet. Lies within the habitable zone[6][10] 38
Janssen
8.6 0.0160.17 Orbits too close to the star[32]40
HD 40307 b[33]≥4.2 0.0470.2 Orbits too close to the star[34]42
HD 40307 c[33]≥6.8 0.0810.06 Orbits too close to the star[34]42
HD 40307 d [35]
≥9.2 0.1340.07 Orbits too close to the star[36]42
HD 40307 e ≥3.5 0.1886 0.15 Orbits too close to the star [3]42
HD 40307 f ≥5.2 385°K 0.247 0.02 Orbits too close to the star [3]42
HD 40307 g ≥7.1 284 K[37] 0.600 0.290.79[38] Mesoplanet [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[39] was announced.[40][41] 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.[40][41]

Statistics

Distance from the Solar System
Distance Lying within
the habitable zone 		All
< 10 light-years 0 1
< 20 light-years 7 15
< 30 light-years 8 18
< 40 light-years 9 19
< 50 light-years 10 26
Earth Similarity Index
ESI Number of planets Notes
0.90-1.00 0 ESI of Earth is 1
0.80-0.89 2
0.70-0.79 6
< 0.70 2 ESI of Mars is 0.64
No data 20
Habitable class
Class Number of planets
Mesoplanet:
medium-temperature (0–50 °C)		 6
Psychroplanet:
cold temperature (-50 - 0 °C)		 2
Thermoplanet:
hot temperature (50 - 100 °C)		 3
Questionable habitability 1
Non-habitable 17

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 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, arXiv:1108.3447, Bibcode:2011yCat..35349058P, 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". arXiv:1211.1617v1 [astro-ph].
  4. ↑ "Stars within 50 light years". Retrieved 3 October 2015.
  5. ↑ "G stars within 100 light-years". Retrieved 3 October 2015.
  6. 1 2 3 "[1403.0430] Bayesian search for low-mass planets around nearby M dwarfs. Estimates for occurrence rate based on global detectability statistics". Retrieved 3 October 2015. line feed character in |title= at position 83 (help)
  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. arXiv:1311.6806. Bibcode:2013PNAS..11019273P. 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. 1 2 3 "HEC: Data of Potentially Habitable Worlds - Planetary Habitability Laboratory @ UPR Arecibo". Retrieved 3 October 2015.
  11. 1 2 "Two planets orbit nearby ancient star". Retrieved 3 October 2015.
  12. ↑ Fogg, M. J.; Nelson, R. P. (2005). "Oligarchic and giant impact growth of terrestrial planets in the presence of gas giant planet migration". Astronomy and Astrophysics 441 (2): 791–806. arXiv:astro-ph/0507180. Bibcode:2005A&A...441..791F. doi:10.1051/0004-6361:20053453.
  13. ↑ Rivera, E. et al. (2005). "A ~7.5 M⊕ Planet Orbiting the Nearby Star, GJ 876". The Astrophysical Journal 634 (1): 625–640
  14. ↑ 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\".
  15. ↑ "Super-Earths". Retrieved 3 October 2015.
  16. ↑ http://www.hpcf.upr.edu/~abel/phl/tuomi/hec_orbit_GJ_682_b.png
  17. ↑ "A Nearby Super-Earth with the Right Temperature but Extreme Seasons - Planetary Habitability Laboratory @ UPR Arecibo". Retrieved 3 October 2015.
  18. ↑ Vogt, S. S.; et al. (2010). \"The Lick-Carnegie Exoplanet Survey: A 3.1 M_Earth Planet in the Habitable Zone of the Nearby M3V Star Gliese 581
  19. ↑ Valencia; Sasselov, Dimitar D.; O'Connell, Richard J. (2006). "Radius and Structure Models of the First Super-Earth Planet". The Astrophysical Journal 656 (1): 545–551. arXiv:astro-ph/0610122. Bibcode:2007ApJ...656..545V. doi:10.1086/509800.
  20. ↑ von Bloh et al. (2007). "The Habitability of Super-Earths in Gliese 581". Astronomy and Astrophysics 476 (3): 1365–1371.
  21. ↑ Vogt, S. S.; et al. (2010). \"The Lick-Carnegie Exoplanet Survey: A 3.1 M_Earth Planet in the Habitable Zone of the Nearby M3V Star Gliese 581\".
  22. ↑ von Bloh, W.; Bounama, C.; Cuntz, M.; Franck, S. (2007). "The Habitability of Super-Earths in Gliese 581". Astronomy & Astrophysics 476 (3): 1365–1371. arXiv:0705.3758. Bibcode:2007A&A...476.1365V. doi:10.1051/0004-6361:20077939.
  23. 1 2 3 4 5 6 7 8 9 10 11 12 The Habitable Exoplanets Catalog. The values are just the best estimates and are subject to change.
  24. ↑ M. Mayor, X. Bonfils, T. Forveille, X. Delfosse, S. Udry, J.-L. Bertaux, H. Beust, F. Bouchy, C. Lovis, F. Pepe, C. Perrier, D. Queloz, N. C. Santos (2009). "The HARPS search for southern extra-solar planets,XVIII. An Earth-mass planet in the GJ 581 planetary system".
  25. ↑ Vogt, S. S.; et al. (2010). \"The Lick-Carnegie Exoplanet Survey: A 3.1 M⊕ Planet in the Habitable Zone of the Nearby M3V Star Gliese 581
  26. ↑ Bonfils; Delfosse; Udry; Forveille; Mayor; Perrier; Bouchy; Gillon; Lovis (2011). "The HARPS search for southern extra-solar planets XXXI. The M-dwarf sample". arXiv:1111.5019 [astro-ph.EP].
  27. ↑ "A Potential Habitable Exoplanet in a Nearby Triple Star System - Planetary Habitability Laboratory @ UPR Arecibo". Retrieved 3 October 2015.
  28. ↑ Vogt, Steven; Wittenmyer; Paul Butler; Simon O'Toole; Henry; Rivera; Stefano Meschiari; Gregory Laughlin; Tinney (2009). "A Super-Earth and two Neptunes Orbiting the Nearby Sun-like star 61 Virginis". arXiv:0912.2599v1 [astro-ph.EP].
  29. ↑ Vogt, Steven (2009). \"A Super-Earth and two Neptunes Orbiting the Nearby Sun-like star 61 Virginis
  30. ↑ Kaltenegger, L; Udry, S; Pepe, F (2011). "A Habitable Planet around HD 85512?" 1108: 3561. arXiv:1108.3561. Bibcode:2011arXiv1108.3561K.
  31. 1 2 Kaltenegger, L.; Udry, S.; Pepe, F. (2011). A Habitable Planet around HD 85512?
  32. ↑ Rebekah et al.; Fabrycky (2010-05-21). \"Radial velocity planets de-aliased. A new, short period for Super-Earth 55 Cnc e\". The Astrophysical Journal 722: 937–953
  33. 1 2 M. Mayor, S. Udry, C. Lovis, F. Pepe, D. Queloz, W. Benz, J.-L. Bertaux, F. Bouchy, C. Mordasini, D. Segransan (2009). "The HARPS search for southern extra-solar planets. XIII. A planetary system with 3 Super-Earths (4.2, 6.9, & 9.2 Earth masses)". Astronomy and Astrophysics 493 (2): 639–644. arXiv:0806.4587. Bibcode:2009A&A...493..639M. doi:10.1051/0004-6361:200810451.
  34. 1 2 M. Mayor, S. Udry, C. Lovis, F. Pepe, D. Queloz, W. Benz, J.-L. Bertaux, F. Bouchy, C. Mordasini, D. Segransan (2009). \"The HARPS search for southern extra-solar planets. XIII. A planetary system with 3 Super-Earths (4.2, 6.9, & 9.2 Earth masses)\". Astronomy and Astrophysics 493 (2): 639–644
  35. ↑ Barnes, R., Jackson, B., Raymond, S., West, A., Greenberg, R. (2009). "The HD 40307 Planetary System: Super-Earths or Mini-Neptunes?". The Astrophysical Journal 695 (2): 1006. arXiv:0901.1698. Bibcode:2009ApJ...695.1006B. doi:10.1088/0004-637X/695/2/1006.
  36. ↑ M. Mayor, S. Udry, C. Lovis, F. Pepe, D. Queloz, W. Benz, J.-L. Bertaux, F. Bouchy, C. Mordasini, D. Segransan (2009). \"The HARPS search for southern extra-solar planets. XIII. A planetary system with 3 Super-Earths (4.2, 6.9, & 9.2 Earth masses)\". Astronomy and Astrophysics 493 (2): 639–644.
  37. ↑ "HEC: Data of Potential Habitable Worlds". University of Puerto Rico at Arecibo (Planetary Habitability Laboratory). November 12, 2012.
  38. ↑ "First Potential Habitable Exoplanet in a Six-Planet Star System - Planetary Habitability Laboratory @ UPR Arecibo". Retrieved 3 October 2015.
  39. ↑ Staff (September 20, 2012). "LHS 188 -- High proper-motion Star". Centre de données astronomiques de Strasbourg(Strasbourg astronomical Data Center). Retrieved September 20, 2012.
  40. 1 2 Méndez, Abel (August 29, 2012). "A Hot Potential Habitable Exoplanet around Gliese 163". University of Puerto Rico at Arecibo (Planetary Habitability Laboratory). Retrieved September 20, 2012.
  41. 1 2 Redd, Nola Taylor (September 20, 2012). "Newfound Alien Planet a Top Contender to Host Life". Space.com. Retrieved September 20, 2012.

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