# Alpha Centauri <!-- SOLSIM:BEGIN g31 — Solar System explorer state (hand-built on wt-core, specs/solar/); do not hand-edit inside --> **Microsim — three.js (Wikitube framework):** *Out to the nearest star (Solar System explorer)* <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/solar/Solar_System.html?view=neighborhood&embed=1" data-title="Out to the nearest star (Solar System explorer)"></div> *The Solar System explorer locked on this article's state (`?view=neighborhood`); every object and population of the [[PORTAL_Solar_System|Solar System portal]] has its own state in the same scene.* <!-- SOLSIM:END --> *Try: follow the ruler to its far end, the tick for Proxima Centauri at 4.25 light-years, and compare it with the Oort cloud tick at about 2,000 AU and the Hill sphere tick at about 200,000 AU; set show to clouds and boundaries to leave the Oort cloud points reaching toward the star; press l to hide the labels and drag the view edge-on to see how thin the planets' region is against the distance to the nearest star.* **Alpha Centauri** (α Centauri, α Cen) is the star system nearest to the [[Sun]], in the southern constellation Centaurus. It has three stars: Rigil Kentaurus (α Centauri A) and Toliman (α Centauri B), two stars much like the Sun that orbit each other every 80 years, and Proxima Centauri (α Centauri C), a faint red dwarf that circles the pair far out.[^iau-wgsn][^akeson2021] Proxima is the closest known star to the Sun, 1.302 parsecs or 4.25 light-years away, and the A–B pair lies at 1.332 parsecs (4.34 light-years).[^gaia-dr3][^akeson2021] To the naked eye A and B merge into a single star of magnitude −0.27, the third brightest in the night sky after Sirius and Canopus.[^philips2002] Proxima Centauri has two confirmed planets: Proxima b, of about Earth's mass in the star's [[Habitable_zone|habitable zone]], and Proxima d, smaller and closer in. A third, Proxima c, remains disputed, and a giant planet candidate imaged around Alpha Centauri A in 2024 awaits confirmation.[^anglada2016][^suarez2025][^beichman2025] The system is the first destination named for interstellar probes.[^starshot] The explorer at the top of this page ends where this system begins. Its neighbourhood view is a ruler from the heliopause out to a tick for Proxima Centauri at 4.25 light-years, about 269,000 [[Astronomical_unit|AU]]; the Alpha Centauri stars themselves, their orbits and their planets are not drawn. ## Etymology and nomenclature The designation α Centauri comes from Johann Bayer's star atlas of 1603, which lettered the stars of each constellation roughly in order of brightness. Centaurus is the centaur of Greek myth, and Alpha marks one of its front hooves.[^earthsky] The traditional name Rigil Kentaurus is a Latinised form of the Arabic *Rijl al-Qinṭūrus*, "the foot of the centaur", itself built on the Greek name of the constellation.[^kunitzsch2006] Toliman goes back to Jacob Golius's 1669 edition of the astronomical compendium of al-Farghānī, where it renders an Arabic name meaning "the two ostriches".[^kunitzsch2006][^golius1669] Proxima Centauri was found by Robert Innes in 1915, and Innes proposed the name Proxima Centaurus because the star seemed slightly nearer than the bright pair.[^innes1915][^innes1917] When the International Astronomical Union's Working Group on Star Names decided in 2016 to name individual stars rather than whole systems, it restricted Rigil Kentaurus to component A and approved Proxima Centauri for C; Toliman was approved for B on 10 August 2018.[^iau-wgsn][^iau-csn] ### Other names Chinese astronomy places the star in the asterism Nán Mén, the Southern Gate, formed with Epsilon Centauri, so Alpha Centauri is Nán Mén Èr, the second star of the Southern Gate.[^aeea2006] For the Boorong people of northwestern Victoria, Australia, Alpha and Beta Centauri are two brothers who hunted and killed the emu that the Coalsack nebula represents.[^hamacher2010][^stanbridge1857] ## Observation Alpha Centauri is the outer of the two Southern Pointers: a line from Beta Centauri, about 4.5° to its west, through Alpha leads to the Southern Cross, which is how observers tell the true cross from the fainter False Cross.[^hartung1994] South of about latitude 29° S the star never sets; north of about 29° N it never rises.[^norton1986] The two bright components are separated on the sky by between about 2 and 22 arcseconds as they orbit, too close for the eye but easy in binoculars or a small telescope for most of the 80-year cycle.[^aitken1961][^hartung1994] Proxima lies 2.2° southwest of the pair, about four times the apparent width of the full [[Moon]], and at magnitude about 11 it needs a moderate telescope. It is a flare star that can brighten by more than half a magnitude within minutes.[^matthews1993][^benedict1998] ### Observational history Ptolemy included the star in the catalogue of the *Almagest* in the 2nd century, when precession still carried it above the horizon of Alexandria.[^ptolemy] The Jesuit Jean Richaud saw that it was double in December 1689 while observing a comet from Puducherry in India, making it only the third binary star recognized.[^kameswara1984] Its distance was among the first measured for any star. Thomas Henderson, at the Cape of Good Hope, measured its parallax from observations made in 1832 and 1833, but doubted a shift that implied so close a star and published only in 1839, after Friedrich Bessel had announced the parallax of 61 Cygni in 1838.[^pannekoek1989][^henderson1839] Positional measurements of the pair followed with John Herschel's micrometer in 1834 and with photographic plates in the 20th century, and by 1926 William Finsen had derived orbital elements close to those used today.[^herschel1847][^aitken1961] Innes identified Proxima in 1915 by comparing plates taken years apart: the faint star shared the proper motion and parallax of the bright pair and seemed slightly closer than it.[^innes1915] ## Location and motion Alpha Centauri lies just beyond the Sun's local cloud; it is thought to be inside the neighbouring G cloud, next to the [[Local_Interstellar_Cloud|Local Interstellar Cloud]] within the larger [[Local_Bubble|Local Bubble]].[^linsky2019] The nearest known system to it is the binary brown dwarf Luhman 16, 3.6 light-years away.[^boffin2014] ### Historical distance estimates Parallax is the half-yearly shift of a nearby star against distant ones as [[Earth]] moves around its [[Orbit|orbit]]; a star with a parallax of one arcsecond is one parsec away. Henderson's value of 1.16 arcseconds put the pair at 0.86 parsecs, 35 percent too close; the ALMA measurement of 2021 gives 750.81 milliarcseconds, a precision of about 0.05 percent.[^henderson1839][^akeson2021] | Measurement | Year | Parallax (mas) | Distance (pc) | Distance (ly) | |---|---|---|---|---| | Henderson | 1839 | 1,160 | 0.86 | 2.8 | | Gill and Elkin | 1885 | 750 | 1.33 | 4.35 | | Hipparcos (Perryman et al.) | 1997 | 742.12 | 1.348 | 4.40 | | ALMA (Akeson et al.) | 2021 | 750.81 | 1.332 | 4.34 | Sources: Henderson; Gill and Elkin; the Hipparcos Catalogue; Akeson and colleagues. Distances in parsecs are 1,000 divided by the parallax in milliarcseconds (derived).[^henderson1839][^gill1885][^hipparcos1997][^akeson2021] ### Kinematics The system crosses the sky quickly compared with other bright stars, a result of its nearness to the [[Sun]]. The centre of mass of A and B moves about 3.7 arcseconds a year, roughly 1° every thousand years, which corresponds to about 23 km/s westward and 4.4 km/s northward at its distance; spectroscopy adds an approach speed of about 22.4 km/s.[^kervella2016] Combining the three components gives a speed relative to the Sun of about 32 km/s (derived). The motion was first noticed by Manuel Johnson and used by Henderson, who compared his positions with those measured by Lacaille in 1751–1752.[^pannekoek1989] Because the system lies almost in the plane of the [[Milky_Way|Milky Way]] as seen from Earth, it often passes in front of background stars. In May 2028 α Centauri A is predicted to pass in front of a distant red star with a 45 percent chance of an Einstein ring forming, and such conjunctions allow very precise astrometry that may also reveal planets.[^kervella2016] Alpha Centauri is approaching: around the year 27,000 it will pass the Sun at about 0.9 parsecs, after which it will recede.[^matthews1994][^bailerjones2015] ## Stellar system Alpha Centauri is a hierarchical triple. A and B form a close binary, and Proxima orbits the pair at a distance so great that, seen from Proxima, A and B act almost as a single mass; the notation AB–C describes this arrangement.[^heintz1978] ### Orbital properties A and B orbit their common centre of mass, under their mutual [[Gravity|gravity]], every 79.76 years on an ellipse of eccentricity 0.52. Their separation swings between about 11.2 AU at periastron, roughly the Sun–[[Saturn]] distance, and about 35.6 AU at apastron, roughly the Sun–[[Pluto]] distance. The last periastron was in 1955 and the next falls in 2035.[^akeson2021][^hartkopf2008] The orbit also weighs the stars. The mean separation, about 23.3 AU (derived from the 17.49-arcsecond semi-major axis and the parallax), and the period give, by [[Kepler's_laws_of_planetary_motion|Kepler's third law]], a total mass of 23.3³/79.76² ≈ 1.99 solar masses (derived), matching the 1.079 and 0.909 solar masses found for A and B.[^akeson2021] Whether Proxima is bound to the pair was long uncertain, because its small orbital speed was hard to separate from measurement error. Precise radial velocities settled the question in 2017.[^kervella2017] Proxima lies about 13,000 AU from A and B, some 430 times the radius of [[Neptune|Neptune's]] orbit.[^kervella2017] Its orbit takes about 511,000 years, with an eccentricity of about 0.5 that carries it between about 4,100 and 12,300 AU from the pair.[^akeson2021] ### Physical properties | Star | Spectral type | Mass (Sun = 1) | Radius (Sun = 1) | Luminosity (Sun = 1) | |---|---|---|---|---| | α Centauri A | G2V | 1.079 | 1.22 | 1.51 | | α Centauri B | K1V | 0.909 | 0.86 | 0.50 | | Proxima Centauri | M (red dwarf) | about 0.12 | — | — | Values for A and B from Akeson and colleagues; Proxima's mass from Kervella and colleagues.[^akeson2021][^kervella2017] Alpha Centauri A has the Sun's spectral type and nearly its surface temperature but about 8 percent more mass; like the Sun it shines by the [[Nuclear_fusion|fusion]] of [[Hydrogen|hydrogen]] into [[Helium|helium]] in its core. A star of that mass would ordinarily be hotter; A is cooler because it is richer in heavy elements and has evolved further, so that its surface has expanded and cooled while its total output has risen to about one and a half times the Sun's.[^nsamba2019] B is an orange K dwarf, fainter overall but brighter in X-rays than A, and more magnetically active, with an activity cycle of about 8 years against the Sun's 11.[^robrade2005][^ayres2014] In 2005 A's coronal activity fell into a deep minimum that has been compared with the Sun's Maunder Minimum.[^ayres2014] Ages from stellar oscillations, together with [[Spectroscopy|spectroscopic]] constraints, range from about 4.85 to 6.5 billion years, and estimates from activity and rotation give about 4.4 to 5.0 billion years, so the pair is about as old as the [[Sun]] or somewhat older.[^thevenin2002][^eggenberger2004][^mamajek2008] Proxima is a flare star of about an eighth of the Sun's mass, far too faint to be seen without a telescope.[^kervella2017][^benedict1998] ## Planetary system Only Proxima Centauri has confirmed planets, which makes it the nearest known [[Planetary_system|planetary system]] to the Sun. Claims around A and B continue to appear and to be tested. ### Planets of Alpha Centauri A In 2021 Wagner and colleagues, using a mid-infrared imager on the Very Large Telescope, reported a candidate signal, called C1, at about 1.1 AU from A, inside the star's habitable zone; it might be a planet between Neptune and Saturn in size, a dust cloud or an artefact.[^wagner2021] In August 2024 the James Webb Space Telescope's mid-infrared coronagraph found a point source about 2 AU from A that is not a background object. If it is a planet, it is a cold gas giant of about 90 to 150 Earth masses with a temperature near 225 K; it was not seen again in 2025, possibly because it had moved along its orbit.[^beichman2025][^sanghi2025] ### Planets of Alpha Centauri B In 2012 Dumusque and colleagues announced Alpha Centauri Bb, an Earth-mass planet on a 3.2-day orbit, from radial velocities.[^dumusque2012] A reanalysis in 2016 showed that the signal came from the way the observations were spaced in time, not from a planet.[^rajpaul2016] A Hubble search for transits of Bb found one possible event that could belong to a different, short-period planet, which has not been confirmed.[^demory2015] ### Planets of Proxima Centauri Proxima b was announced by a team led by Guillem Anglada-Escudé in 2016; it was the first [[Earth]]-mass planet found around the nearest star. It orbits every 11.2 days at about 0.049 AU, in the star's habitable zone, with a minimum mass of about 1.17 Earth masses.[^anglada2016][^suarez2020] Being so close to a flaring red dwarf, it receives far more X-ray and ultraviolet radiation than Earth and may be tidally locked, so whether it could be habitable is uncertain.[^anglada2016] Proxima d, with a minimum mass of about a quarter of Earth's and a 5.1-day orbit, was reported in 2022 and confirmed with the near-infrared NIRPS spectrograph in 2025.[^faria2022][^suarez2025] Proxima c, a candidate of several Earth masses on an orbit of about 1.5 AU and some five years, was published in 2020.[^damasso2020] A 2022 analysis disputed it, and NIRPS data in 2025 found only hints of a weaker signal at a similar period.[^artigau2022][^suarez2025] ### Hypothetical planets Because A and B resemble the Sun in age and composition, they are prime targets for planet searches, but their mutual gravity limits where planets can survive. Orbits around either star are stable only within a few AU, well inside the region where [[Jupiter]] and [[Saturn]] orbit the Sun.[^wiegert1997] Simulations suggest that [[Terrestrial_planet|rocky planets]] could have formed in B's habitable zone, which lies between about 0.7 and 1.2 AU, and in A's, between about 1.2 and 2.1 AU, although the companion's pull makes growth from planetesimals harder.[^kaltenegger2013][^thebault2009][^quintana2002] Radial-velocity surveys have ruled out [[Gas_giant|giant planets]] in close orbits and reached sensitivity to planets of a few Earth masses in B's habitable zone without a detection.[^dumusque2012][^zhao2018] ### Circumstellar discs Observations from 2007 to 2012 found a slight excess of infrared emission at 24 μm around the pair. If real, it would come from a thin disc of dust with 10 to 100 times the mass of the Sun's [[Interplanetary_dust_cloud|zodiacal dust cloud]], stable out to about 2.8 AU around A and 2.5 AU around B. That would put A's disc entirely inside its [[Frost_line_(astrophysics)|frost line]] and only the outer edge of B's beyond it.[^wiegert2014] ## View from this system From Alpha Centauri the constellations would look much as they do from Earth, because the system is so close to the Sun relative to most bright stars. The [[Sun]] itself would appear in Cassiopeia, opposite Alpha Centauri's position in our sky, as a star of magnitude about +0.5.[^king2022] The number follows from the distance: the Sun's absolute magnitude of 4.83 at 1.332 parsecs gives an apparent magnitude of 4.83 + 5 log₁₀(1.332/10) ≈ +0.45 (derived).[^akeson2021] A planet orbiting one of the pair would see the other as an extremely bright star. From an orbit 1.25 AU from A, where A's light would match the Sun's on Earth, star B would be about 10 to 37 AU away as the pair moves along its 80-year orbit, and so between about 190 and 2,600 times fainter than A (derived from the stars' luminosities and separations), yet still far brighter than a full [[Moon]].[^akeson2021] Proxima would appear from A or B only as a modest star of about fourth to fifth magnitude.[^drewex2020] ## Future exploration Distance is the obstacle. At [[Voyager_1|Voyager 1's]] speed of about 17 km/s, crossing 4.37 light-years would take about 77,000 years (derived). Breakthrough Starshot, announced in 2016, proposes gram-scale probes on light sails pushed by ground-based lasers to about a fifth of the speed of light, which would reach the system in about 20 years and send back images of any planets.[^starshot][^overbye2016] The discovery of Proxima b a few months later gave the concept a specific target.[^chang2016] In 2017 engineers at NASA's Jet Propulsion Laboratory sketched a mission to launch in 2069, the centenary of Apollo 11. At a tenth of the speed of light it would arrive after 44 years, and its signals would take more than four years to return; the idea has not been developed into a funded mission.[^wenz2017] ## In culture The star is prominent in the navigation and sky lore of [[Earth|Earth's]] Southern Hemisphere. Polynesian navigators used it; in Ngarrindjeri tradition in South Australia, Alpha and Beta Centauri are two sharks chasing a stingray; and in Inca tradition the pair are the eyes of a llama-shaped dark cloud in the Milky Way.[^earthsky] As the nearest star, Alpha Centauri is also a fixed point of scale models of the cosmos: the Sagan Planet Walk in Ithaca, New York, a walkable model of the [[Solar_System_model|Solar System]], placed its Alpha Centauri marker at the ʻImiloa Astronomy Center in Hawaii.[^couillard2012] ## See also - [[Local_Interstellar_Cloud]] · [[Local_Bubble]] - [[Habitable_zone]] - [[Planetary_system]] - [[Oort_cloud]] - [[Voyager_1]] - Proxima Centauri · Proxima Centauri b · Breakthrough Starshot · List of nearest stars ## Notes Distances in this article use the 2021 ALMA parallax for A and B and the Gaia Data Release 3 parallax for Proxima. Values marked "derived" are computed here from the cited quantities. ## References [^iau-wgsn]: International Astronomical Union (2016). "IAU Working Group on Star Names (WGSN)". https://www.iau.org/science/scientific_bodies/working_groups/280/ [^akeson2021]: Akeson, R.; Beichman, C.; Kervella, P.; Fomalont, E.; Benedict, G. F. (2021). "Precision millimeter astrometry of the α Centauri AB system". *The Astronomical Journal* 162: 14. https://doi.org/10.3847/1538-3881/abfaff [^gaia-dr3]: Gaia Collaboration; Vallenari, A.; et al. (2023). "Gaia Data Release 3: summary of the content and survey properties". *Astronomy & Astrophysics* 674: A1. https://doi.org/10.1051/0004-6361/202243940 [^philips2002]: *Philip's Astronomy Encyclopedia* (2002). Philip's. ISBN 978-0-540-07863-9. [^anglada2016]: Anglada-Escudé, G.; Amado, P. J.; Barnes, J.; et al. (2016). "A terrestrial planet candidate in a temperate orbit around Proxima Centauri". *Nature* 536: 437–440. https://doi.org/10.1038/nature19106 [^suarez2025]: Suárez Mascareño, A.; Artigau, É.; et al. (2025). "Diving into the planetary system of Proxima with NIRPS: breaking the metre per second barrier in the infrared". *Astronomy & Astrophysics* 700: A11. https://doi.org/10.1051/0004-6361/202553728 [^beichman2025]: Beichman, C.; et al. (2025). "Worlds next door: a candidate giant planet imaged in the habitable zone of α Cen A. I. Observations, orbital and physical properties, and exozodi upper limits". *The Astrophysical Journal Letters* 989: L22. https://doi.org/10.3847/2041-8213/adf53f [^sanghi2025]: Sanghi, A.; et al. (2025). "Worlds next door: a candidate giant planet imaged in the habitable zone of α Cen A. II. Binary star modeling, planet and exozodi search, and sensitivity analysis". *The Astrophysical Journal Letters* 989: L23. https://doi.org/10.3847/2041-8213/adf53e [^starshot]: Breakthrough Initiatives. "Starshot". https://breakthroughinitiatives.org/Initiative/3 [^earthsky]: EarthSky (16 April 2023). "Alpha Centauri, the star system closest to our sun". https://earthsky.org/brightest-stars/alpha-centauri-is-the-nearest-bright-star/ [^kunitzsch2006]: Kunitzsch, P.; Smart, T. (2006). *A Dictionary of Modern Star Names: A Short Guide to 254 Star Names and Their Derivations*. Sky Publishing, p. 27. ISBN 978-1-931559-44-7. [^golius1669]: al-Farghānī, A. ibn M.; Golius, J. (ed.) (1669). *Elementa astronomica, Arabicè & Latinè*. Amsterdam: Jansonius à Waasberge, p. 76. https://books.google.com/books?id=OvWTSYvB0TYC&pg=PA76 [^innes1915]: Innes, R. T. A. (1915). "A faint star of large proper motion". *Circular of the Union Observatory Johannesburg* 30: 235–236. Bibcode 1915CiUO...30..235I. [^innes1917]: Innes, R. T. A. (1917). "Parallax of the faint proper motion star near alpha of Centaurus". *Circular of the Union Observatory Johannesburg* 40: 331–336. Bibcode 1917CiUO...40..331I. [^iau-csn]: International Astronomical Union. "IAU Catalog of Star Names". http://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt [^aeea2006]: Activities of Exhibition and Education in Astronomy (AEEA), National Museum of Natural Science, Taiwan (27 June 2006). Chinese star names (天文教育資訊網). [^hamacher2010]: Hamacher, D. W.; Frew, D. J. (2010). "An Aboriginal Australian record of the Great Eruption of Eta Carinae". *Journal of Astronomical History and Heritage* 13: 220–234. https://doi.org/10.3724/SP.J.1440-2807.2010.03.06 [^stanbridge1857]: Stanbridge, W. M. (1857). "On the astronomy and mythology of the Aborigines of Victoria". *Transactions of the Philosophical Institute of Victoria* 2: 137–140. [^hartung1994]: Hartung, E. J.; Frew, D.; Malin, D. (1994). *Astronomical Objects for Southern Telescopes*. Melbourne University Press, p. 194. ISBN 978-0-522-84553-2. [^norton1986]: Norton, A. P.; Ridpath, I. (ed.) (1986). *Norton's 2000.0: Star Atlas and Reference Handbook*. Longman Scientific and Technical, pp. 39–40. [^aitken1961]: Aitken, R. G. (1961). *The Binary Stars*. Dover, pp. 235–237. [^matthews1993]: Matthews, R. A. J.; Gilmore, G. (1993). "Is Proxima really in orbit about α Cen A/B?". *Monthly Notices of the Royal Astronomical Society* 261: L5–L7. https://doi.org/10.1093/mnras/261.1.l5 [^benedict1998]: Benedict, G. F.; McArthur, B.; Nelan, E.; et al. (1998). "Proxima Centauri: time-resolved astrometry of a flare site using HST Fine Guidance Sensor 3". *ASP Conference Series* 154: 1212. Bibcode 1998ASPC..154.1212B. [^ptolemy]: Toomer, G. J. (trans.) (1984). *Ptolemy's Almagest*. Gerald Duckworth & Co., p. 368, note 136. ISBN 978-0-7156-1588-1. [^kameswara1984]: Kameswara-Rao, N.; Vagiswari, A.; Louis, C. (1984). "Father J. Richaud and early telescope observations in India". *Bulletin of the Astronomical Society of India* 12: 81. Bibcode 1984BASI...12...81K. [^pannekoek1989]: Pannekoek, A. (1989). *A History of Astronomy*. Dover, pp. 333, 345–346. ISBN 978-0-486-65994-7. [^henderson1839]: Henderson, T. (1839). "On the parallax of α Centauri". *Monthly Notices of the Royal Astronomical Society* 4: 168–169. https://doi.org/10.1093/mnras/4.19.168 [^herschel1847]: Herschel, J. F. W. (1847). *Results of Astronomical Observations Made During the Years 1834, 5, 6, 7, 8 at the Cape of Good Hope*. Smith, Elder and Co. Bibcode 1847raom.book.....H. [^linsky2019]: Linsky, J. L.; Redfield, S.; Tilipman, D. (2019). "The interface between the outer heliosphere and the inner local ISM: morphology of the Local Interstellar Cloud, its hydrogen hole, Strömgren shells, and ⁶⁰Fe accretion". *The Astrophysical Journal* 886: 41. https://doi.org/10.3847/1538-4357/ab498a [^boffin2014]: Boffin, H. M. J.; Pourbaix, D.; Mužić, K.; et al. (2014). "Possible astrometric discovery of a substellar companion to the closest binary brown dwarf system WISE J104915.57–531906.1". *Astronomy & Astrophysics* 561: L4. https://doi.org/10.1051/0004-6361/201322975 [^gill1885]: Gill, D.; Elkin, W. L. (1885). "Heliometer-determinations of stellar parallax in the southern hemisphere". *Memoirs of the Royal Astronomical Society* 48: 1–194. Bibcode 1885MmRAS..48....1G. [^hipparcos1997]: Perryman, M. A. C.; et al. (1997). *The Hipparcos and Tycho Catalogues*. ESA SP-1200; entries HIP 71681 and HIP 71683. VizieR catalogue I/239. [^kervella2016]: Kervella, P.; Mignard, F.; Mérand, A.; Thévenin, F. (2016). "Close stellar conjunctions of α Centauri A and B until 2050: an mK = 7.8 star may enter the Einstein ring of α Cen A". *Astronomy & Astrophysics* 594: A107. https://doi.org/10.1051/0004-6361/201629201 [^matthews1994]: Matthews, R. A. J. (1994). "The close approach of stars in the solar neighbourhood". *Quarterly Journal of the Royal Astronomical Society* 35: 1–8. Bibcode 1994QJRAS..35....1M. [^bailerjones2015]: Bailer-Jones, C. A. L. (2015). "Close encounters of the stellar kind". *Astronomy & Astrophysics* 575: A35. https://doi.org/10.1051/0004-6361/201425221 [^heintz1978]: Heintz, W. D. (1978). *Double Stars*. D. Reidel, p. 19. ISBN 978-90-277-0885-4. [^hartkopf2008]: Hartkopf, W. I.; Mason, B. D. (2008). *Sixth Catalog of Orbits of Visual Binary Stars*. U.S. Naval Observatory. http://ad.usno.navy.mil/wds/orb6.html [^kervella2017]: Kervella, P.; Thévenin, F.; Lovis, C. (2017). "Proxima's orbit around α Centauri". *Astronomy & Astrophysics* 598: L7. https://doi.org/10.1051/0004-6361/201629930 [^nsamba2019]: Nsamba, B.; Campante, T. L.; Monteiro, M. J. P. F. G.; Cunha, M. S.; et al. (2019). "On the nature of the core of α Centauri A: the impact of the metallicity mixture". *Frontiers in Astronomy and Space Sciences* 6: 25. https://doi.org/10.3389/fspas.2019.00025 [^robrade2005]: Robrade, J.; Schmitt, J. H. M. M.; Favata, F. (2005). "X-rays from α Centauri – the darkening of the solar twin". *Astronomy & Astrophysics* 442: 315–321. https://doi.org/10.1051/0004-6361:20053314 [^ayres2014]: Ayres, T. R. (2014). "The ups and downs of α Centauri". *The Astronomical Journal* 147: 59. https://doi.org/10.1088/0004-6256/147/3/59 [^thevenin2002]: Thévenin, F.; Provost, J.; Morel, P.; et al. (2002). "Asteroseismology and calibration of α Cen binary system". *Astronomy & Astrophysics* 392: L9–L12. https://doi.org/10.1051/0004-6361:20021074 [^eggenberger2004]: Eggenberger, P.; Charbonnel, C.; Talon, S.; et al. (2004). "Analysis of α Centauri AB including seismic constraints". *Astronomy & Astrophysics* 417: 235–246. https://doi.org/10.1051/0004-6361:20034203 [^mamajek2008]: Mamajek, E. E.; Hillenbrand, L. A. (2008). "Improved age estimation for solar-type dwarfs using activity-rotation diagnostics". *The Astrophysical Journal* 687: 1264–1293. https://doi.org/10.1086/591785 [^wagner2021]: Wagner, K.; Boehle, A.; Pathak, P.; et al. (2021). "Imaging low-mass planets within the habitable zone of α Centauri". *Nature Communications* 12: 922. https://doi.org/10.1038/s41467-021-21176-6 [^dumusque2012]: Dumusque, X.; Pepe, F.; Lovis, C.; et al. (2012). "An Earth-mass planet orbiting α Centauri B". *Nature* 491: 207–211. https://doi.org/10.1038/nature11572 [^rajpaul2016]: Rajpaul, V.; Aigrain, S.; Roberts, S. J. (2016). "Ghost in the time series: no planet for Alpha Cen B". *Monthly Notices of the Royal Astronomical Society: Letters* 456: L6–L10. https://doi.org/10.1093/mnrasl/slv164 [^demory2015]: Demory, B.-O.; Ehrenreich, D.; Queloz, D.; et al. (2015). "Hubble Space Telescope search for the transit of the Earth-mass exoplanet α Centauri Bb". *Monthly Notices of the Royal Astronomical Society* 450: 2043–2051. https://doi.org/10.1093/mnras/stv673 [^suarez2020]: Suárez Mascareño, A.; Faria, J. P.; Figueira, P.; et al. (2020). "Revisiting Proxima with ESPRESSO". *Astronomy & Astrophysics* 639: A77. https://doi.org/10.1051/0004-6361/202037745 [^faria2022]: Faria, J. P.; Suárez Mascareño, A.; Figueira, P.; et al. (2022). "A candidate short-period sub-Earth orbiting Proxima Centauri". *Astronomy & Astrophysics* 658: A115. https://doi.org/10.1051/0004-6361/202142337 [^damasso2020]: Damasso, M.; Del Sordo, F.; Anglada-Escudé, G.; et al. (2020). "A low-mass planet candidate orbiting Proxima Centauri at a distance of 1.5 AU". *Science Advances* 6: eaax7467. https://doi.org/10.1126/sciadv.aax7467 [^artigau2022]: Artigau, É.; Cadieux, C.; Cook, N. J.; et al. (2022). "Line-by-line velocity measurements: an outlier-resistant method for precision velocimetry". *The Astronomical Journal* 164: 84. https://doi.org/10.3847/1538-3881/ac7ce6 [^wiegert1997]: Wiegert, P. A.; Holman, M. J. (1997). "The stability of planets in the Alpha Centauri system". *The Astronomical Journal* 113: 1445–1450. https://doi.org/10.1086/118360 [^kaltenegger2013]: Kaltenegger, L.; Haghighipour, N. (2013). "Calculating the habitable zone of binary star systems. I. S-type binaries". *The Astrophysical Journal* 777: 165. https://doi.org/10.1088/0004-637X/777/2/165 [^thebault2009]: Thébault, P.; Marzari, F.; Scholl, H. (2009). "Planet formation in the habitable zone of α Centauri B". *Monthly Notices of the Royal Astronomical Society: Letters* 393: L21–L25. https://doi.org/10.1111/j.1745-3933.2008.00590.x [^quintana2002]: Quintana, E. V.; Lissauer, J. J.; Chambers, J. E.; Duncan, M. J. (2002). "Terrestrial planet formation in the Alpha Centauri system". *The Astrophysical Journal* 576: 982–996. https://doi.org/10.1086/341808 [^zhao2018]: Zhao, L.; Fischer, D. A.; Brewer, J.; Giguere, M.; Rojas-Ayala, B. (2018). "Planet detectability in the Alpha Centauri system". *The Astronomical Journal* 155: 24. https://doi.org/10.3847/1538-3881/aa9bea [^wiegert2014]: Wiegert, J.; Liseau, R.; Thébault, P.; et al. (2014). "How dusty is α Centauri? Excess or non-excess over the infrared photospheres of main-sequence stars". *Astronomy & Astrophysics* 563: A102. https://doi.org/10.1051/0004-6361/201321887 [^king2022]: King, B. (2 February 2022). "See the Sun from other stars". *Sky & Telescope*. https://skyandtelescope.org/astronomy-blogs/explore-night-bob-king/see-the-sun-from-other-stars/ [^drewex2020]: LePage, A. (28 August 2020). "Alien skies: the view from Alpha Centauri". *Drew Ex Machina*. https://www.drewexmachina.com/2020/08/28/alien-skies-the-view-from-alpha-centauri/ [^overbye2016]: Overbye, D. (12 April 2016). "A visionary project aims for Alpha Centauri, a star 4.37 light-years away". *The New York Times*. https://www.nytimes.com/2016/04/13/science/alpha-centauri-breakthrough-starshot-yuri-milner-stephen-hawking.html [^chang2016]: Chang, K. (24 August 2016). "One star over, a planet that might be another Earth". *The New York Times*. https://www.nytimes.com/2016/08/25/science/earth-planet-proxima-centauri.html [^wenz2017]: Wenz, J. (19 December 2017). "NASA has begun plans for a 2069 interstellar mission". *New Scientist*. https://www.newscientist.com/article/mg23631576-000-exclusive-nasa-has-begun-plans-for-a-2069-interstellar-mission/ [^couillard2012]: Couillard, S. "Sagan Planet Walk expands to Hawaii". *Cornell Daily Sun*. http://cornellsun.com/node/53167 ## External links - European Southern Observatory, "A family portrait of the Alpha Centauri system" (2003): http://www.eso.org/public/news/eso0307/ - European Southern Observatory, "Planet found in habitable zone around nearest star" (2016): https://www.eso.org/public/news/eso1629/ - NASA Exoplanet Archive, Proxima Centauri system: https://exoplanetarchive.ipac.caltech.edu/overview/Proxima%20Cen - Breakthrough Starshot: https://breakthroughinitiatives.org/Initiative/3 ### Hypothetical planets or exploration - Project Longshot (NASA/US Naval Academy design study, 1988) · Breakthrough Starshot · Proxima Centauri b ## Wikipedia : Wikitube **Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Alpha_Centauri) : [Wikitube](https://en.wikitube.io/wiki/Alpha_Centauri) · pinned revision [1375471581](https://en.wikipedia.org/w/index.php?oldid=1375471581) · 2026-09-18 ## Previous hub tags Hubs: `Life_Physics`. Portals: [[PORTAL_Solar_System]]. --- *Solar System portal child articles, wave 1 · 2026-09-18 · drafted · row SOL-090 · explorer state `?view=neighborhood`.* <!-- hub_tags: Life_Physics · PORTAL_Solar_System -->