The closest recent approach was in February 2016, at 4.0 arcsec through the PA of 300°.  The observational thresholds for planet detection in the habitable zones by the radial velocity method are currently (2017) estimated to be about 50 M⊕ for Alpha Centauri A, 8 M⊕ for Alpha Centauri B, and 0.5 M⊕ for Proxima Centauri. It has a minimum mass of 1.17 M⊕ (Earth masses) and orbits approximately 0.049 AU from Proxima Centauri, placing it in the star's habitable zone. It lies just 4.3 light-years from the Earth and one component in a triple star system. Although it has a lower luminosity than A, Alpha Centauri B emits more energy in the X-ray band. Alpha Centauri (Latinized from α Centauri, abbreviated Alpha Cen or α Cen) is the closest star system and closest planetary system to the Solar System at 4.37 light-years (1.34 parsec) from the Sun. Change the fate of humanity by conquering space in Sid Meier's Alpha Centauri. Tolimân is Golius' latinisation of the Arabic name الظلمان al-Ẓulmān "the ostriches", the name of an asterism of which Alpha Centauri formed the main star. Get breaking space news and the latest updates on rocket launches, skywatching events and more! With the placement of the Sun east of the magnitude 3.4 star Epsilon Cassiopeiae, nearly in front of the Heart Nebula, the "W" line of stars of Cassiopeia would have a "/W" shape. Alpha Centauri – A Voyage to Alpha Centauri, Alpha Centauri – Associação de Astronomia (Portuguese), "Nearest Star System Might Harbor Earth Twin", https://en.wikipedia.org/w/index.php?title=Alpha_Centauri&oldid=988855876, Astronomical objects known since antiquity, Planetary systems with one confirmed planet, Articles with Chinese-language sources (zh), Short description is different from Wikidata, Articles containing Chinese-language text, Creative Commons Attribution-ShareAlike License, This page was last edited on 15 November 2020, at 17:39. , Together, Alpha and Beta Centauri form the "Southern Pointers" or "The Pointers", as they point towards the Southern Cross, the asterism of the constellation of Crux. Alpha Centauri A is about 10 percent more massive than the Sun, with a radius about 22 percent larger. If [humanity's fastest-moving spacecraft] Voyager had left our planet when humans first left Africa, travelling at 11 miles a second, it would be arriving at Alpha Centauri just about now."  It is more magnetically active than Alpha Centauri A, showing a cycle of 8.2±0.2 yr compared to 11 years for the Sun, and about half the minimum-to-peak variation in coronal luminosity of the Sun.  Alpha Centauri B has an apparent magnitude of +1.35, slightly dimmer than Mimosa..  Despite these difficulties, given the similarities to the Sun in spectral types, star type, age and probable stability of the orbits, it has been suggested that this stellar system could hold one of the best possibilities for harbouring extraterrestrial life on a potential planet. , The large proper motion of Alpha Centauri AB was discovered by Manuel John Johnson, observing from Saint Helena, who informed Thomas Henderson at the Royal Observatory, Cape of Good Hope of it.  Proxima Centauri appears as a deep-red star of a typical apparent magnitude of 11.1 in a sparsely populated star field, requiring moderately sized telescopes to be seen.  It is the closest star to the Sun but is too faint to be visible to the naked eye.  When considered among the individual brightest stars in the sky (excluding the Sun), it is the fourth brightest at an apparent magnitude of −0.01, being slightly fainter than Arcturus at an apparent magnitude of −0.05. , The sky from Alpha Centauri AB would appear much as it does from the Earth, except that Centaurus would be missing its brightest star. , Whilst ruling out the existence of Alpha Centauri Bb, a possible transit of a separate exoplanet in 2013 was observed. Other conjunctions will also occur in the coming decades, allowing accurate measurement of proper motions and possibly giving information on planets.  At nearest approach, Alpha Centauri will attain a maximum apparent magnitude of −0.86, comparable to present-day magnitude of Canopus, but it will still not surpass that of Sirius, which will brighten incrementally over the next 60,000 years, and will continue to be the brightest star as seen from Earth (other than the Sun) for the next 210,000 years. For example, in about 6,200 AD, α Centauri's true motion will cause an extremely rare first-magnitude stellar conjunction with Beta Centauri, forming a brilliant optical double star in the southern sky.  Age estimates for the stars based on chromospheric activity (Calcium H & K emission) yield 4.4 ± 2.1 Gyr, whereas gyrochronology yields 5.0±0.3 Gyr. The closest star system to the Earth is the famous Alpha Centauri group. , Asteroseismic studies, chromospheric activity, and stellar rotation (gyrochronology) are all consistent with the Alpha Centauri system being similar in age to, or slightly older than, the Sun. And then it could be time to go take a look. Sixth Catalogue of Orbits of Visual Binary Stars U.S.N.O. To reach the system within a human lifetime, one would need to travel at one-tenth of the speed of light.  The name Proxima Centauri later became more widely used and is now listed by the IAU as the approved proper name. Astronomers first realized the bright star Alpha Centauri was a tightly orbiting pair in 1689, and Proxima Centauri was first spotted in 1915. Since then, researchers have tried to verify the planet's existence using transits — a slight dimming in the star as the planet passes by — but haven't found additional, conclusive evidence. The two unmanned probes, Voyager 1 and Voyager 2, launched in 1977, are not headed toward the system, but if they were, it would take them tens of thousands of years to get there. In fact, some astronomers question whether it's part of the system at all, or just passing through. The first of these is that bright Star in the sterne of Argo which they call Canobus. Alpha Centauri lies close to the southern horizon when viewed from the 29° N latitude to the equator (close to Hermosillo, Chihuahua City in Mexico, Galveston, Texas, Ocala, Florida and Lanzarote, the Canary Islands of Spain), but only for a short time around its culmination.  Were it a planetary companion, it would have to be at most 0.29 Earth masses, but it could also be random noise found in the data. Using spectroscopy the mean radial velocity has been determined to be around 22.4 km/s towards the Solar System.  The star culminates each year at local midnight on 24 April and at local 9 p.m. on 8 June. or one-thousandth of an arcsec. Join our Space Forums to keep talking space on the latest missions, night sky and more!  Stellar evolution theory implies both stars are slightly older than the Sun at 5 to 6 billion years, as derived by their mass and spectral characteristics.. The instrument, which is part of the European Space Agency's La Silla Observatory in Chile, measured tiny wobbles in the star that suggested that a planet was orbiting it — likely just a bit bigger than Earth, orbiting its star every 3.24 days. Alpha Centauri is an independent multi-asset management boutique founded in 2005 and based in Hamburg, Germany. , South of about 29° S latitude, Alpha Centauri is circumpolar and never sets below the horizon. The third [Alpha Centauri] is in the right foote of the Centaure. , Proxima Centauri b is a terrestrial planet discovered in 2016 by astronomers at the European Southern Observatory. A spinoff of the popular Civilization series is Sid Meier's Alpha Centauri. He withheld his results, however, because he suspected they were too large to be true, but eventually published them in 1839 after Friedrich Wilhelm Bessel released his own accurately determined parallax for 61 Cygni in 1838. The Sun would appear as a yellow star of apparent magnitude +0.47, roughly the same as the average brightness of Betelgeuse from Earth. Its mass is calculated to be 0.1221 M☉. Alpha Centauri is the closest star system to the Solar System.