Alpha Centauri


Also found in: Dictionary, Thesaurus, Acronyms, Wikipedia.
Related to Alpha Centauri: Proxima Centauri, Andromeda galaxy

Alpha Centauri

(ăl`fə sĕntôr`ē), brightest star in the constellation CentaurusCentaurus
, southern constellation located N and E of Crux, the Southern Cross. It is known especially for its bright stars Alpha Centauri and Hadar. It also contains Centaurus A, a radio galaxy, as well as a globular star cluster visible to the naked eye.
..... Click the link for more information.
 and 3d-brightest star in the sky; also known as Rigil Kent or Rigil Kentaurus; 1992 position R.A. 14h39.1m, Dec. −60°49'. Its apparent magnitudemagnitude,
in astronomy, measure of the brightness of a star or other celestial object. The stars cataloged by Ptolemy (2d cent. A.D.), all visible with the unaided eye, were ranked on a brightness scale such that the brightest stars were of 1st magnitude and the dimmest stars
..... Click the link for more information.
 is −0.26. Alpha Centauri is actually a triple-star system, the components being designated A, B, and C. Alpha Centauri A is the brightest component; it is a yellow main-sequence star of the same spectral classspectral class,
in astronomy, a classification of the stars by their spectrum and luminosity. In 1885, E. C. Pickering began the first extensive attempt to classify the stars spectroscopically.
..... Click the link for more information.
 (G2 V) as the sun and of about the same size and mass. It forms a binary system with the somewhat smaller, less bright, and more orange Alpha Centauri B. Alpha Centauri C, a red dwarf, is also called Proxima Centauri because it is the closest star to the earth (other than the sun), at a distance of 4.28 light-years; components A and B are currently 4.34 light-years away. Proxima Centauri orbits about the common center of mass of the system with a period of more than 250,000 years, so that in about 125,000 years it will be more distant than A and B. In 2012 the discovery of a roughly earth-sized planet orbiting Alpha Centauri B was announced; the planet was reported to orbit the star closer than Mercury orbits the sun. A roughly earth-sized planet has also been identified (2016) orbiting Proxima Centauri. Though it orbits its star much more closely than the Mercury does the sun, it is believed to be in the habitable zone because of the cooler temperatures of Proxima Centauri; however, the star is of a type that tends to produce solar flares readily, which would bombard the nearby planet with high levels of radiation and strip any atmosphere from it.

Alpha Centauri

(sen-tor -ÿ, -ee) (Rigil Kentaurus; α Cen) A binary star that is the brightest star in the constellation Centaurus, one of the brightest in the sky, and the second nearest star to the Sun. The two components, A and B, form a yellow-orange visual binary (separation 17″.7, period 80.1 years) and are similar in mass and size to the Sun. Proxima Centauri appears to be physically associated with α Cen; it is the nearest star to the Sun. mv : –0.01 (A), 1.33 (B), –0.27 (AB); Mv : 4.4 (A), 5.7 (B), 4.1 (AB); spectral type: G2 V (A), K1 V (B); mass: 1.09 (A), 0.89 (B) times solar mass; distance: 1.33 pc.

Alpha Centauri

[¦al·fə sen′tȯ·rē]
(astronomy)
A double star, the brightest in the constellation Centaurus; apart from the sun, it is the nearest bright star to earth, about 4.3 light-years away; spectral classification G2. Also known as Rigil Kent.

Alpha Centauri

brightest star in Centaurus constellation; closest star to Earth. [Astronomy: NCE, 74]
References in periodicals archive ?
The data collected by Chandra revealed Alpha Centauri A, which is the near twin of our Sun in every way, even age, emits a lower dose of x-ray radiation compared to that received by planets sitting in close proximity of our Sun.
Perhaps some were so disappointed by the false alarm in 2012, when another group claimed to have found an exoplanet in the Alpha Centauri system, no one wanted to get their hopes up.
It is the faintest of the three, which also include a much brighter pair of stars known as Alpha Centauri A and B.
Travelling at such speeds, the robotic spacecraft will pass Pluto in three days and will reach Alpha Centauri within 20 years after launch.
As the third Breakthrough initiative in the past four years, Breakthrough Starshot will test the area and technologies which are needed to send a featherweight robot spacecraft to the Alpha Centauri star system, at a distance of 4.37 light years: that is, 40,000,000,000,000 kilometres or 25 trillion miles.
The other reaching for Alpha Centauri or wherever it is You've
Our closest group of stars, The Alpha Centauri star system begins to collapse and the resulting gravity waves reach our planet, creating strange phenomena around the globe leaving the people who are affected by them wondering what in the world is going on.
"This technique could be instrumental in searching for life in Alpha Centauri, the planetary system closest to the Sun," says Berdyugina.
The sellers of South Palawan shares are Giantlead Prestige, Inc., Alpha Centauri Fortune Group, Inc., Antares Nickel Capital, Inc., Huatai Investment Holding Pty.
They reached Alpha Centauri, 4.4 light years away, in 1968 and 5 years later they stretched out to Sirius, 8.6 light years away.