Astronomy:List of nearest terrestrial exoplanet candidates

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This list of nearest terrestrial exoplanet candidates contains possible terrestrial ("rocky") exoplanets spaced 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.

Exoplanets discovered (incomplete)

This list is incomplete, currently containing 34 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 could 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] Eleven billion of these estimated planets may be orbiting Sun-like stars.[9] The nearest such planet was then as close as 12 light-years away[7][8] but (see below) is now estimated slightly above four light-years away.

On August 24, 2016, astronomers announced the discovery of a rocky planet in the habitable zone of Proxima Centauri, the closest star to Earth (not counting the Sun). 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 75%.[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]

Data Table

Name M🜨 R🜨 g Ts a e [s] D
Proxima Centauri b ≥1.27 ~1.1 234 K
-39°C
0.05 <0.35 [10] 4.22
Proxima Centauri c ~7 39 K
-234 °C[13]
~1.489 ~0.04 4.22
Barnard's Star b ≥3.23 105 K
-168.15 °C
0.404 0.32 [14] 5.958
Ross 128 b ≥1.40 213 to 301 K
-60 to 28 °C
11.03
Luyten b ≥2.89 ≥1.35 259 K
-14 °C
0.091 0.10 12.20
Wolf 1061b ≥1.36 ≥1.44 -
-
13.8
Wolf 1061c ≥4.3 ≥1.64 -
-
[15] 13.8
Wolf 1061d ≥5.21 ≥2.04 -
-
13.8
Gliese 876 d[16] 6.8 650 K
377 °C[17]
0.021 0.21 [18] 15
Gliese 682 b ≥2 -
-
[6]
[19]
[15]
16
Gliese 832 c ≥5.4 251 K
-22 °C
0.162 0.03 [20][21] 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 -
-
0.029 0 [22] 20
Gliese 581 c[23] ≥5.6 -
-
0.072 0 [22] 20
Gliese 581 d[24] ≥5.6 2.34[25] 1.27[25] 233 K
-41 °C[25]
0.218 0 [22] 20
HD 219134 b 4.5 1.6 700 K
427 °C
[26] 21
Gliese 667 Cb 6.30 1.44 445 K

172 °C

0.05 0.09 [25] 22
Gliese 667 Cc[27][28] 3.8 1.32 302 K
29 °C
0.13 0.34 [25] 22
61 Virginis b[29] ≥5.1 -
-
0.050 0.12 [30] 28
HD 85512 b[31] ≥3.6 1.74[25] 1.33[25] 351 K
78 °C[25]
0.26 0.11 [32] 36
GJ 180 b ≥2.3 312 K
39 °C
[6][20] 38
TRAPPIST-1b -
-
[33] 39.5
TRAPPIST-1c -
-
[33] 39.5
TRAPPIST-1d 0.48 282.1 K
9 °C[25]
[33] 39.5
TRAPPIST-1e 246.1 K
-27.1 °C[25]
[33] 39.5
TRAPPIST-1f 219 K
-54 °C[25]
[33] 39.5
TRAPPIST-1g 198.6 K
-75 °C[25]
[33] 39.5
TRAPPIST-1h 169 K
-104 °C[25]
[33] 39.5
55 Cancri e
(Janssen)
8.6 -
-
0.016 0.17 [34] 40
HD 40307 b[35] ≥4.2 -
-
0.047 0.2 [35] 42
HD 40307 c[35] ≥6.8 -
-
0.081 0.06 [35] 42
HD 40307 d[36] ≥9.2 -
-
0.134 0.07 [35] 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[37]
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[38] was announced.[39][40] 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.[39][40] 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?) 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. 1.0 1.1 1.2 1.3 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, doi:10.1051/0004-6361/201117055, Bibcode2011A&A...534A..58P 
  2. 2.0 2.1 2.2 2.3 Schneider, Jean, Star: HD 20794, Paris Observatory, http://exoplanet.eu/star.php?st=HD+20794, retrieved 2011-12-05 
  3. 3.0 3.1 3.2 3.3 Tuomi, Mikko; Anglada-Escudé, Guillem; Gerlach, Enrico; Jones, Hugh R. A.; Reiners, Ansgar; Rivera, Eugenio J.; Vogt, Steven S.; Butler, R. Paul (17 December 2012). "Habitable-zone super-Earth candidate in a six-planet system around the K2.5V star HD 40307". Astronomy & Astrophysics 549: A48. doi:10.1051/0004-6361/201220268. Bibcode2013A&A...549A..48T. 
  4. "Stars within 50 light years". http://www.atlasoftheuniverse.com/50lys.html. 
  5. "G stars within 100 light-years". http://www.solstation.com/stars3/100-gs.htm. 
  6. 6.0 6.1 6.2 Tuomi, Mikko; Jones, Hugh R. A.; Barnes, John R.; Anglada-Escudé, Guillem; Jenkins, James S. (2014). "Bayesian search for low-mass planets around nearby M dwarfs. Estimates for occurrence rate based on global detectability statistics". Monthly Notices of the Royal Astronomical Society 441 (2): 1545–1569. doi:10.1093/mnras/stu358. Bibcode2014MNRAS.441.1545T. 
  7. 7.0 7.1 Overbye, Dennis (November 4, 2013). "Far-Off Planets Like the Earth Dot the Galaxy". New York Times. https://www.nytimes.com/2013/11/05/science/cosmic-census-finds-billions-of-planets-that-could-be-like-earth.html. 
  8. 8.0 8.1 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. doi:10.1073/pnas.1319909110. PMID 24191033. Bibcode2013PNAS..11019273P. 
  9. Khan, Amina (November 4, 2013). "Milky Way may host billions of Earth-size planets". Los Angeles Times. http://www.latimes.com/science/la-sci-earth-like-planets-20131105,0,2673237.story. 
  10. 10.0 10.1 Anglada-Escudé, Guillem; Amado, Pedro J.; Barnes, John et al. (2016). "A terrestrial planet candidate in a temperate orbit around Proxima Centauri". Nature 536 (7617): 437–440. doi:10.1038/nature19106. PMID 27558064. Bibcode2016Natur.536..437A. http://www.eso.org/public/archives/releases/sciencepapers/eso1629/eso1629a.pdf. 
  11. Billings, Lee. "Miniature Space Telescope Could Boost the Hunt for "Earth Proxima"". http://www.scientificamerican.com/article/miniature-space-telescope-could-boost-the-hunt-for-earth-proxima-video. 
  12. "The Search for Earth Proxima". https://www.theatlantic.com/video/index/492266/the-search-for-earth-proxima. 
  13. Wall, Mike (12 April 2019). "Possible 2nd Planet Spotted Around Proxima Centauri". https://www.space.com/proxima-centauri-possible-second-exoplanet.html. 
  14. https://www.eso.org/public/archives/releases/sciencepapers/eso1837/eso1837a.pdf Template:Bare URL PDF
  15. 15.0 15.1 "HEC: Data of Potentially Habitable Worlds - Planetary Habitability Laboratory @ UPR Arecibo". http://phl.upr.edu/projects/habitable-exoplanets-catalog/data. 
  16. 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. doi:10.1051/0004-6361:20053453. Bibcode2005A&A...441..791F. http://www.aanda.org/articles/aa/full/2005/38/aa3453-05/aa3453-05.html. 
  17. Rivera, E. (2005). "A ~7.5 M🜨 Planet Orbiting the Nearby Star, GJ 876". The Astrophysical Journal 634 (1): 625–640. doi:10.1086/491669. Bibcode2005ApJ...634..625R. 
  18. 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".
  19. http://www.hpcf.upr.edu/~abel/phl/tuomi/hec_orbit_GJ_682_b.png Template:Bare URL image
  20. 20.0 20.1 "HEC: Data of Potentially Habitable Worlds - Planetary Habitability Laboratory @ UPR Arecibo". http://phl.upr.edu/projects/habitable-exoplanets-catalog/data. 
  21. "A Nearby Super-Earth with the Right Temperature but Extreme Seasons - Planetary Habitability Laboratory @ UPR Arecibo". http://phl.upr.edu/press-releases/gliese832. 
  22. 22.0 22.1 22.2 Vogt, S. S. (2010). "The Lick-Carnegie Exoplanet Survey: A 3.1 M_Earth Planet in the Habitable Zone of the Nearby M3V Star Gliese 581". The Astrophysical Journal 723 (1): 954–965. doi:10.1088/0004-637x/723/1/954. Bibcode2010ApJ...723..954V. 
  23. Valencia; Sasselov, Dimitar D.; O'Connell, Richard J. (2007). "Radius and Structure Models of the First Super-Earth Planet". The Astrophysical Journal 656 (1): 545–551. doi:10.1086/509800. Bibcode2007ApJ...656..545V. 
  24. von Bloh, W.; Bounama, C.; Cuntz, M.; Franck, S. (2007). "The Habitability of Super-Earths in Gliese 581". Astronomy & Astrophysics 476 (3): 1365–1371. doi:10.1051/0004-6361:20077939. Bibcode2007A&A...476.1365V. 
  25. 25.00 25.01 25.02 25.03 25.04 25.05 25.06 25.07 25.08 25.09 25.10 25.11 25.12 The Habitable Exoplanets Catalog. The values are just the best estimates and are subject to change.
  26. "Astronomers find star with three super-Earths". http://phys.org/news/2015-07-astronomers-star-super-earths.html. 
  27. Bonfils, Xavier; Delfosse, Xavier; Udry, Stéphane; Forveille, Thierry; Mayor, Michel; Perrier, Christian; Bouchy, François; Gillon, Michaël et al. (2011). "The HARPS search for southern extra-solar planets XXXI. The M-dwarf sample". Astronomy and Astrophysics: A109. doi:10.1051/0004-6361/201014704. Bibcode2013A&A...549A.109B. 
  28. "A Potential Habitable Exoplanet in a Nearby Triple Star System - Planetary Habitability Laboratory @ UPR Arecibo". http://phl.upr.edu/press-releases/apotentialhabitableexoplanetinanearbytriplestarsystem. 
  29. Vogt, Steven; Wittenmyer; Paul Butler; Simon O'Toole; Henry; Rivera; Stefano Meschiari; Gregory Laughlin et al. (2010). "A Super-Earth and two Neptunes Orbiting the Nearby Sun-like star 61 Virginis". The Astrophysical Journal 708 (2): 1366–1375. doi:10.1088/0004-637X/708/2/1366. Bibcode2010ApJ...708.1366V. 
  30. Vogt, Steven (2009). \"A Super-Earth and two Neptunes Orbiting the Nearby Sun-like star 61 Virginis
  31. Kaltenegger, L; Udry, S; Pepe, F (2011). A Habitable Planet around HD 85512?. 1108. pp. 3561. Bibcode2011arXiv1108.3561K. 
  32. Kaltenegger, L.; Udry, S.; Pepe, F. (2011). A Habitable Planet around HD 85512?
  33. 33.0 33.1 33.2 33.3 33.4 33.5 33.6 Gillon, M; Triaud, AH; Demory, BO; Jehin, E; Agol, E; Deck, KM; Lederer, SM; de Wit, J et al. (2017). "Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1". Nature 542 (7642): 456–460. doi:10.1038/nature21360. PMID 28230125. PMC 5330437. Bibcode2017Natur.542..456G. http://www.eso.org/public/archives/releases/sciencepapers/eso1706/eso1706a.pdf. 
  34. Rebekah (2010). "Radial velocity planets de-aliased. A new, short period for Super-Earth 55 Cnc e". The Astrophysical Journal 722 (1): 937–953. doi:10.1088/0004-637x/722/1/937. Bibcode2010ApJ...722..937D. 
  35. 35.0 35.1 35.2 35.3 35.4 M. Mayor; S. Udry; C. Lovis; F. Pepe; D. Queloz; W. Benz; J.-L. Bertaux; F. Bouchy et al. (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. doi:10.1051/0004-6361:200810451. Bibcode2009A&A...493..639M. 
  36. 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): 1006–1011. doi:10.1088/0004-637X/695/2/1006. Bibcode2009ApJ...695.1006B. 
  37. "HEC: Data of Potential Habitable Worlds". University of Puerto Rico at Arecibo (Planetary Habitability Laboratory). November 12, 2012. http://phl.upr.edu/projects/habitable-exoplanets-catalog/data. 
  38. Staff (September 20, 2012). "LHS 188 -- High proper-motion Star". Centre de données astronomiques de Strasbourg(Strasbourg astronomical Data Center). http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HIP+19394. 
  39. 39.0 39.1 Méndez, Abel (August 29, 2012). "A Hot Potential Habitable Exoplanet around Gliese 163". University of Puerto Rico at Arecibo (Planetary Habitability Laboratory). http://phl.upr.edu/press-releases/ahotpotentialhabitableexoplanetaroundgliese163. 
  40. 40.0 40.1 Redd, Nola Taylor (September 20, 2012). "Newfound Alien Planet a Top Contender to Host Life". Space.com. http://www.space.com/17684-alien-planet-gliese-163c-extraterrestrial-life.html. 

External links