Alpha Centauri

Alpha Centauri is the brightest object in the constellation of Centaurus (top left).
Apparent and true orbits of Alpha Centauri. The A component is held stationary, and the relative orbital motion of the B component is shown. The apparent orbit (thin ellipse) is the shape of the orbit as seen by an observer on Earth. The true orbit is the shape of the orbit viewed perpendicular to the plane of the orbital motion. According to the radial velocity versus time, the radial separation of A and B along the line of sight had reached a maximum in 2007, with B being further from Earth than A. The orbit is divided here into 80 points: each step refers to a timestep of approx. 0.99888 years or 364.84 days.
The relative sizes and colours of stars in the Alpha Centauri system, compared to the Sun
Relative positions of Sun, Alpha Centauri AB and Proxima Centauri. Grey dot is projection of Proxima Centauri, located at the same distance as Alpha Centauri AB.
The two bright stars at the lower right are Alpha (right) and Beta Centauri (left, above antenna). A line drawn through them points to the four bright stars of the Southern Cross, just to the right of the dome of the Danish 1.54 m telescope at La Silla Observatory in Chile.
Alpha Centauri AB taken in daylight by holding a Canon Powershot S100 in line with the eyepiece of a 110-mm refractor. The photo is one of the best frames of a video. The double star is clearly visible.
View of Alpha Centauri from the Digitized Sky Survey-2
Alpha Centauri A is of the same stellar type G2 as the Sun, while Alpha Centauri B is a K1-type star.
Closest stars to the Sun
Distances of the nearest stars from 20,000 years ago until 80,000 years in the future
Animation showing motion of Alpha Centauri through the sky. (The other stars are held fixed for didactic reasons) "Oggi" means today. "Anni" means years.
The discovery image of Alpha Centauri's candidate Neptunian planet, marked here as "C1".
Looking towards the sky around Orion from Alpha Centauri with Sirius near Betelgeuse, Procyon in Gemini, and the Sun in Cassiopeia generated by Celestia.
Simulated night-sky image with a "W" of stars from Cassiopeia connected by lines, and the Sun, labeled "Sol", as it would appear to the left of the "W"
The Very Large Telescope and Alpha Centauri

For other uses, see Alpha Centauri (disambiguation).

- Alpha Centauri
Alpha Centauri is the brightest object in the constellation of Centaurus (top left).

41 related topics

Alpha

Directors general of ESO (from left to right): Lodewijk Woltjer, Harry van der Laan, Catherine Cesarsky, Tim de Zeeuw and Xavier Barcons

European Southern Observatory

Intergovernmental research organisation made up of 16 member states for ground-based astronomy.

Intergovernmental research organisation made up of 16 member states for ground-based astronomy.

Directors general of ESO (from left to right): Lodewijk Woltjer, Harry van der Laan, Catherine Cesarsky, Tim de Zeeuw and Xavier Barcons
La Silla cluster of telescopes
The ESO 3.6 m Telescope
The New Technology Telescope
Dome of the Danish 1.54-metre telescope that has been in operation at La Silla Observatory since 1979.
A 360-degree panoramic view of the southern night sky from Paranal, with telescopes in foreground
The Very Large Telescope and the star system Alpha Centauri.
Globular Cluster 47 Tucanae
ESO science archive
Artist's impression of ESO Supernova Planetarium & Visitor Centre.
ESOcast is a video podcast series with the latest news and research in astronomy.
VISTA's infrared view of the Orion Nebula
The Helix Nebula
The Globular Cluster Omega Centauri
A 340-million pixel starscape from Paranal
NGC 2264 and the Christmas Tree cluster
The Centre of the Milky Way
NGC 2467 and Surroundings
The Horsehead Nebula
Messier 78: a reflection nebula in Orion
The WR 22 and Eta Carinae regions of the Carina Nebula
The hidden fires of the Flame Nebula
Early morning on Paranal
The future ALMA array on Chajnantor (artist's rendering)
Rare 360-degree Panorama of the Southern Sky
370-million-pixel starscape of the Lagoon Nebula
The Milky Way panorama
The Omega Nebula
Centaurus A
Glowing Stellar Nurseries
The R Coronae Australis region imaged with the Wide Field Imager at La Silla

In August 2016, the European Southern Observatory announced the detection of a planet orbiting the third star in the Alpha Centauri system, Proxima Centauri.

Robert T. A. Innes

Scottish astronomer best known for discovering Proxima Centauri in 1915, and numerous binary stars.

Scottish astronomer best known for discovering Proxima Centauri in 1915, and numerous binary stars.

In 1915, he found a faint star fairly close to and sharing the same large proper motion with Alpha Centauri, which until then was believed to be the closest star system to the Sun.

Star system named DI Cha. While only two stars are apparent, it is actually a quadruple system containing two sets of binary stars.

Beta Centauri

Triple star system in the southern constellation of Centaurus.

Triple star system in the southern constellation of Centaurus.

Star system named DI Cha. While only two stars are apparent, it is actually a quadruple system containing two sets of binary stars.

The Boorong people indigenous to what is now northwestern Victoria, Australia named it Bermbermgle (together with α Centauri), two brothers who were noted for their courage and destructiveness, and who spear and kill Tchingal, "The Emu" (Coalsack Nebula).

Main building of the Royal Observatory, Cape of Good Hope

Royal Observatory, Cape of Good Hope

Oldest continuously existing scientific institution in South Africa.

Oldest continuously existing scientific institution in South Africa.

Main building of the Royal Observatory, Cape of Good Hope
The Observatory in 1857
Plan of the Royal Observatory building, ca 1840.
Thomas Henderson. His Majesty's Astronomer at the Cape, 1831–1833
McClean building
Victoria refractor

The second HM Astronomer, Thomas Henderson, aided by his assistant, Lieutenant William Meadows, made the first observations that led to a believable stellar parallax, namely of Alpha Centauri.

Artistic depiction of Proxima Centauri d, with Alpha Centauri A and B visible in the background

Proxima Centauri d

Artistic depiction of Proxima Centauri d, with Alpha Centauri A and B visible in the background

Proxima Centauri d (also called Proxima d) is a candidate exoplanet orbiting the red dwarf star Proxima Centauri, the closest star to the Sun and part of the Alpha Centauri triple star system.

The Sun, a typical example of a G-type main-sequence star

G-type main-sequence star

Main-sequence star (luminosity class V) of spectral type G. Such a star has about 0.9 to 1.1 solar masses and an effective temperature between about 5,300 and 6,000 K.

Main-sequence star (luminosity class V) of spectral type G. Such a star has about 0.9 to 1.1 solar masses and an effective temperature between about 5,300 and 6,000 K.

The Sun, a typical example of a G-type main-sequence star

Besides the Sun, other well-known examples of G-type main-sequence stars include Alpha Centauri, Tau Ceti, Capella and 51 Pegasi.

Cassiopeia in her chair, as depicted in Urania's Mirror

Cassiopeia (constellation)

Constellation in the northern sky named after the vain queen Cassiopeia, mother of Andromeda, in Greek mythology, who boasted about her unrivaled beauty.

Constellation in the northern sky named after the vain queen Cassiopeia, mother of Andromeda, in Greek mythology, who boasted about her unrivaled beauty.

Cassiopeia in her chair, as depicted in Urania's Mirror
Cassiopeia in the night sky
The constellation Cassiopeia as it can be seen by the naked eye from a northern location
Kappa Cassiopeiae and its bow shock. Spitzer infrared image (NASA/JPL-Caltech)
The Sun would appear close to Cassiopeia from Alpha Centauri
Planetary nebula IC 289 is a cloud of ionised gas being pushed out into space by the remnants of the star's core
Sky image centered in Cassiopeia taken from a dark site. Some deep sky objects are visible, including the Andromeda Galaxy.
Astrophoto of Cassiopeia
Cassiopeia with indication of χ Persei (NGC 884) and h Persei (NGC 869) as well as the star clusters NGC 654, NGC 663, NGC 581 (Messier 103), NGC 457, NGC 225, NGC 7788, NGC 7790, NGC 7789 and NGC 7654 (Messier 52).

If the Earth's Sun could be observed from α Centauri, the closest star to the Solar System, it would be visible in Cassiopeia as a yellow-white 0.5 magnitude star, far brighter than any of the other stars of the constellation.

The Astronomer, 1668, by Johannes Vermeer

Manuel John Johnson

British astronomer.

British astronomer.

The Astronomer, 1668, by Johannes Vermeer

While comparing his results with those of Nicolas Louis de Lacaille he noted the high proper motion of Alpha Centauri and communicated these to Thomas Henderson at the Royal Observatory, Cape of Good Hope.

The constellation Carina with Canopus towards the right (west)

Canopus

Brightest star in the southern constellation of Carina and the second-brightest star in the night sky.

Brightest star in the southern constellation of Carina and the second-brightest star in the night sky.

The constellation Carina with Canopus towards the right (west)
Wide angle view showing Canopus and other prominent stars with the Milky Way
Canopus is the brightest star in the constellation of Carina (top).
Averroes, who used his 1153 observation of Canopus in Marrakesh while the star was invisible in his native Spain as an argument that the earth is round.
Canopus-class battleship HMS Glory

English explorer Robert Hues brought Canopus to the attention of European observers in his 1592 work Tractatus de Globis, along with Achernar and Alpha Centauri, noting: "Now, therefore, there are but three Stars of the first magnitude that I could perceive in all those parts which are never seene here in England. The first of these is that bright Star in the sterne of Argo which they call Canobus. The second is in the end of Eridanus. The third is in the right foote of the Centaure."

People have interpreted patterns and images in the stars since ancient times. This 1690 depiction of the constellation of Leo, the lion, is by Johannes Hevelius.

Epsilon Centauri

Star in the southern constellation of Centaurus.

Star in the southern constellation of Centaurus.

People have interpreted patterns and images in the stars since ancient times. This 1690 depiction of the constellation of Leo, the lion, is by Johannes Hevelius.

In Chinese, 南門 (Nán Mén), meaning Southern Gate, refers to an asterism consisting of ε Centauri and α Centauri.