Alpha Centauri

Alpha CentauriCentauri, α Cen; also known as Rigel Kent /ˈraɪdʒəl ˈkɛnt/—see Names) is the brightest star in the southern constellation of Centaurus, it is currently inside the G-cloud. Although it appears to the unaided eye as a single object, Alpha Centauri is actually a binary star system (designated Alpha Centauri AB or α Cen AB) whose combined visual magnitude of −0.27 makes it the third-brightest star in the night sky after the −1.46 magnitude Sirius and the −0.72 magnitude Canopus.

Its individual component stars are named Alpha Centauri A (α Cen A), with 110% of the mass and 151.9% the luminosity of the Sun, and Alpha Centauri B (α Cen B), at 90.7% of the Sun's mass and 44.5% of its luminosity. During the pair's 79.91-year orbit about a common center, the distance between them varies from about that between Pluto and the Sun to that between Saturn and the Sun. They are 1.34 parsecs or 4.37 light years from the Sun.

A third star, known as Proxima Centauri, Proxima or Alpha Centauri C (α Cen C), is probably gravitationally associated with Alpha Centauri AB. Proxima is at the slightly smaller distance of 1.29 parsecs or 4.21 light years from the Sun, making it the closest star to the Sun, even though it is not visible to the naked eye. The separation of Proxima from Alpha Centauri AB is about 0.06 parsecs, 0.2 light years or 13,000 astronomical units (AU); equivalent to 400 times the size of Neptune's orbit.

The system also contains at least one planet, the Earth-sized Alpha Centauri Bb, which is the closest known exoplanet to Earth. It has a mass at least 113% of Earth's and orbits Alpha Centauri B with a period of 3.236 days. Orbiting at a distance of 6 million kilometers from the star, 4% of the distance of the Earth to the Sun and ten times closer than the orbit of Mercury, the planet has an estimated surface temperature of 1500 K (roughly 1200 °C), too hot to be habitable.

Read more about Alpha Centauri:  Component Designations, Nature of The System, Observation, Observational History, Binary System, Companion: Proxima Centauri, High-proper-motion Star, Apparent Movement, Planets, View From This System, Names, Use in Modern Fiction

Other articles related to "alpha centauri, centauri, alpha":

Stars In Fiction - List of Planetary Systems in Fiction - Proxima Centauri (Alpha Centauri C)
... Proxima Centauri, possibly part of a triple star system with Alpha Centauri A and B, is the nearest known star to the Earth's Solar System ... fiction titles are dedicated to Proxima Centauri, as the destination of humanity's first interstellar voyage ... No claims have been made for the discovery of extrasolar planets in the Proxima Centauri system, although the possibility was explored in the 2005 television documentary Alien Worlds ...
Bartledan - Star Systems - Alpha Centauri - Alpha Proxima
... Alpha Proxima is the smallest (and closest to Earth) member of the Alpha Centauri system ...
Alpha Centauri (disambiguation)
... Alpha Centauri (or α Cen) is a star system and the name of three stars in that system ... It may also refer to Alpha Centauri, a place in The Hitchhiker's Guide to the Galaxy Alpha Centauri, an alien in Doctor Who Sid Meier's Alpha Centauri, a 1999 strategy computer game Alpha ...
Dragon Sun - Reception - Critical Reaction
... Alpha Centauri's science fiction storyline received high praise IGN considered the game an exception to PC sci-fi cliches, and GamePro compared the plot to the works of writers Stanley Kubrick and Isaac Asimov ... ramifications of the final theoretical discoveries elevate Alpha Centauri from great strategy game to science-fiction epic." Game Revolution said, "The well crafted story ... GameSpot reviewer Denny Atkin called the factions and their abilities Alpha Centauri's "most impressive aspect" ...
Alpha Centauri - Use in Modern Fiction
... Alpha Centauri's relative proximity makes it in some ways the logical choice as "first port of call" ...

Famous quotes containing the word alpha:

    Imagination is a valuable asset in business and she has a sister, Understanding, who also serves. Together they make a splendid team and business problems dissolve and the impossible is accomplished by their ministrations.... Imagination concerning the world’s wants and the individual’s needs should be the Alpha and Omega of self-education.
    Alice Foote MacDougall (1867–1945)