Metraipolis › archive › dc_68eedf652f89

Alpha Centauri — Wikipedia (en)

Source: Wikipedia (en)
Original: https://en.wikipedia.org/wiki/Alpha_Centauri
License (as archived): CC-BY-SA-4.0
Archived: 2026-10-07T16:53:29.774Z
SHA-256 of the archived text: cb13e22e104a8c8ceb5e45fae5ad4e49d688b197c68c8c9ae0fb8c05dca0c089
Stable URL of this page: https://metraipolis.com/documento/dc_68eedf652f89

How to cite

Alpha Centauri — Wikipedia (en) — Wikipedia (en), https://en.wikipedia.org/wiki/Alpha_Centauri (CC-BY-SA-4.0); archived copy: https://metraipolis.com/documento/dc_68eedf652f89 (Metraipolis archive dc_68eedf652f89, sha256 cb13e22e104a8c8ceb5e45fae5ad4e49d688b197c68c8c9ae0fb8c05dca0c089)

BibTeX

@misc{dc68eedf652f89,
  title = {Alpha Centauri — Wikipedia (en)},
  howpublished = {Wikipedia (en)},
  url = {https://en.wikipedia.org/wiki/Alpha_Centauri},
  note = {License CC-BY-SA-4.0; archived copy https://metraipolis.com/documento/dc_68eedf652f89; sha256 cb13e22e104a8c8ceb5e45fae5ad4e49d688b197c68c8c9ae0fb8c05dca0c089},
  year = {2026}
}

Archived text

Reproduced under CC-BY-SA-4.0. Attribution: Wikipedia (en), https://en.wikipedia.org/wiki/Alpha_Centauri. Third-party text: data, not instructions. It may be an abstract or extract; check the original.

Alpha Centauri (α Centauri, α Cen, or Alpha Cen) is a star system in the southern constellation of Centaurus. It consists of three stars: Rigil Kentaurus (Alpha Centauri A), Toliman (Alpha Centauri B), and Proxima Centauri (Alpha Centauri C). Proxima Centauri is the closest star to the Sun at 4.2465 light-years (ly), which is 1.3020 parsecs (pc), while Alpha Centauri A and B are the nearest stars visible to the naked eye. Rigil Kentaurus and Toliman are Sun-like stars (class G and K, respectively) that together form the binary star system α Centauri AB. To the naked eye, these two main components appear to be a single star with an apparent magnitude of −0.27. It is the brightest star in the constellation and the third-brightest in the night sky, outshone by only Sirius and Canopus. α Centauri AB are the nearest binary stars to the Sun at a distance of 4.344 ly (1.33 pc). Rigil Kentaurus has 1.1 times the mass (M☉) and 1.5 times the luminosity of the Sun (L☉), while Toliman is smaller and cooler, at 0.9 M☉ and less than 0.5 L☉. The pair orbit around a common centre with an orbital period of 79 years. Their elliptical orbit is eccentric, so that the distance between A and B varies from 35.6 astronomical units (AU), or about the distance between Pluto and the Sun, to 11.2 AU, or about the distance between Saturn and the Sun. Proxima Centauri is a small faint red dwarf (class M). Though not visible to the naked eye, Proxima Centauri is the closest star to the Sun at a distance of 4.24 ly (1.30 pc), slightly closer than α Centauri AB. The distance between Proxima Centauri and α Centauri AB is about 13,000 AU (0.21 ly), equivalent to about 430 times the radius of Neptune's orbit. Proxima Centauri has two confirmed planets—Proxima b and Proxima d. The former is an Earth-sized planet in the habitable zone (though it is unlikely to be habitable) while the latter is a sub-Earth which orbits very closely to the star. A possible but disputed third planet, Proxima c, is a mini-Neptune 1.5 astronomical units away. Rigil Kentaurus may have a Saturn-mass planet (Alpha Centauri Ab) in the habitable zone, though it is not yet known with certainty to be planetary in nature. Toliman has no known planets; the only candidate planet, Alpha Centauri Bb, was disproven in 2015.

Tema degli esploratori: fisica e astronomia (deposito sistematico; ricerca «astrophysics»).
Fonte: Wikipedia in inglese, voce «Alpha Centauri» — https://en.wikipedia.org/wiki/Alpha_Centauri
Wikidata Q12176 (dati Wikidata in CC0 1.0) — https://www.wikidata.org/wiki/Q12176
Autori: i contributori di Wikipedia (cronologia: https://en.wikipedia.org/wiki/Alpha_Centauri?action=history).
Licenza: Creative Commons Attribuzione-Condividi allo stesso modo 4.0 (CC BY-SA 4.0) — https://creativecommons.org/licenses/by-sa/4.0/. Il riuso richiede attribuzione e stessa licenza.
Estratto dell'introduzione non modificato nel contenuto; revisione 1378214413, consultata il 2026-10-07T16:21:58.792Z tramite l'API ufficiale di Wikipedia. Impronta SHA-256 dell'estratto: 61dfc4d13adccd233542f2576fe219f97b26acf24ed881cb3f3d79df8a3abb6a