Centaurus /sɛnˈtɔːrəs/ is a bright constellation in the southern sky. One of the largest constellations, Centaurus was included among the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations. In Greek mythology, Centaurus represents a centaur; a creature that is half human, half horse (another constellation named after a centaur is one from the zodiac: Sagittarius). Notable stars include Alpha Centauri, the nearest star system to the Solar System, its neighbour in the sky Beta Centauri, and V766 Centauri, one of the largest stars yet discovered. The constellation also contains Omega Centauri, the brightest globular cluster as visible from Earth and one of the largest known.
|Pronunciation||/sɛnˈtɔːrəs/, genitive /sɛnˈtɔːraɪ/|
|Right ascension||11h 05m 20.9415s– 15h 03m 11.1071s|
|Area||1060 sq. deg. (9th)|
|Stars with planets||15|
|Stars brighter than 3.00m||10|
|Stars within 10.00 pc (32.62 ly)||8|
|Brightest star||α Cen (−0.27m)|
|Meteor showers||Alpha Centaurids|
|Visible at latitudes between +25° and −90°.|
Best visible at 21:00 (9 p.m.) during the month of May.
Centaurus contains several very bright stars. Its alpha and beta stars are used as "pointer stars" to help observers find the constellation Crux. Centaurus has 281 stars above magnitude 6.5, meaning that they are visible to the unaided eye, the most of any constellation. Alpha Centauri, the closest star system to the Sun, has a high proper motion; it will be a mere half-degree from Beta Centauri in approximately 4000 years.
Alpha Centauri is a triple star system that contains Proxima Centauri, the nearest star to the Sun. Traditionally called Rigil Kentaurus or Toliman, meaning "foot of the centaur", the system has an overall magnitude of -0.28 and is 4.4 light-years from Earth. The primary and secondary are both yellow-hued stars; the primary, is of magnitude -0.01 and the secondary is of magnitude 1.35. Proxima, the tertiary star, is a red dwarf of magnitude 11.0; it is almost 2 degrees away from the primary and secondary and has a period of approximately one million years. Also a flare star, Proxima has minutes-long outbursts where it brightens by over a magnitude. The primary and secondary have a period of 80 years and will be closest to each other as seen from Earth in 2037 and 2038.
In addition to Alpha Centauri (the third-brightest star in the sky), a second first magnitude star, Beta Centauri, is part of Centaurus. Also called Hadar and Agena, Beta Centauri is a double star; the primary is a blue-hued giant star of magnitude 0.6, 525 light-years from Earth. The secondary is of magnitude 4.0 and has a very small separation. A bright binary star in Centaurus is Gamma Centauri, which appears to the naked eye at magnitude 2.2. The primary and secondary are both blue-white hued stars of magnitude 2.9; their period is 84 years.
Centaurus also has many dimmer double stars and binary stars. 3 Centauri is a double star with a blue-white hued primary of magnitude 4.5 and a secondary of magnitude 6.0. The primary is 344 light-years from Earth.
Centaurus is home to many variable stars. R Centauri is a Mira variable star with a minimum magnitude of 11.8 and a maximum magnitude of 5.3; it is about 1,250 light-years from Earth and has a period of 18 months. V810 Centauri is a semiregular variable.
BPM 37093 is a white dwarf star whose carbon atoms are thought to have formed a crystalline structure. Since diamond also consists of carbon arranged in a crystalline lattice (though of a different configuration), scientists have nicknamed this star "Lucy" after the Beatles song "Lucy in the Sky with Diamonds."
PDS 70, (V1032 Centauri) a low mass T Tauri star is found in the constellation Centauras.In July 2018,PDS70 had the first confirmed image of a Protoplanetary disc containing a nascent exoplanet, named PDS 70b.
ω Centauri (NGC 5139), despite being listed as the constellation's "omega" star, is in fact a naked-eye globular cluster, located at a distance of 17,000 light-years with a diameter of 150 light-years. It is the largest and brightest globular cluster in the Milky Way; at ten times the size of the next-largest cluster, it has a magnitude of 3.7. It is also the most luminous globular cluster in the Milky Way, at over one million solar luminosities. Omega Centauri is classified as a Shapley class VIII cluster, which means that its center is loosely concentrated. It is also the only globular cluster to be designated with a Bayer letter; the globular cluster 47 Tucanae is the only one designated with a Flamsteed number. It contains several million stars, most of which are yellow dwarf stars, but also possesses red giants and blue-white stars; the stars have an average age of 12 billion years. This has prompted suspicion that Omega Centauri was the core of a dwarf galaxy that had been absorbed by the Milky Way. Omega Centauri was determined to be nonstellar in 1677 by the English astronomer Edmond Halley, though it was visible as a star to the ancients. Its status as a globular cluster was determined by James Dunlop in 1827. To the unaided eye, Omega Centauri appears fuzzy and is obviously non-circular; it is approximately half a degree in diameter, the same size as the full Moon.
Centaurus is also home to open clusters. NGC 3766 is an open cluster 6,300 light-years from Earth that is visible to the unaided eye. It contains approximately 100 stars, the brightest of which are 7th magnitude. NGC 5460 is another naked-eye open cluster, 2,300 light-years from Earth, that has an overall magnitude of 6 and contains approximately 40 stars.
There is one bright planetary nebula in Centaurus, NGC 3918, also known as the Blue Planetary. It has an overall magnitude of 8.0 and a central star of magnitude 11.0; it is 2600 light-years from Earth. The Blue Planetary was discovered by John Herschel and named for its color's similarity to Uranus, though the nebula is apparently three times larger than the planet.
Centaurus is rich in galaxies as well. NGC 4622 is a face-on spiral galaxy located 200 million light-years from Earth (redshift 0.0146). Its spiral arms wind in both directions, which makes it nearly impossible for astronomers to determine the rotation of the galaxy. Astronomers theorize that a collision with a smaller companion galaxy near the core of the main galaxy could have led to the unusual spiral structure. NGC 5253, a peculiar irregular galaxy, is located near the border with Hydra and M83, with which it likely had a close gravitational interaction 1-2 billion years ago. This may have sparked the galaxy's high rate of star formation, which continues today and contributes to its high surface brightness. NGC 5253 includes a large nebula and at least 12 large star clusters. In the eyepiece, it is a small galaxy of magnitude 10 with dimensions of 5 arcminutes by 2 arcminutes and a bright nucleus. NGC 4945 is a spiral galaxy seen edge-on from Earth, 13 million light-years away. It is visible with any amateur telescope, as well as binoculars under good conditions; it has been described as "shaped like a candle flame", being long and thin (16' by 3'). In the eyepiece of a large telescope, its southeastern dust lane becomes visible. Another galaxy is NGC 5102, found by star-hopping from Iota Centauri. In the eyepiece, it appears as an elliptical object 9 arcminutes by 2.5 arcminutes tilted on a southwest-northeast axis.
One of the closest active galaxies to Earth is the Centaurus A galaxy, NGC 5128, at a distance of 11 million light-years (redshift 0.00183). It has a supermassive black hole at its core, which expels massive jets of matter that emit radio waves due to synchrotron radiation. Astronomers posit that its dust lanes, not common in elliptical galaxies, are due to a previous merger with another galaxy, probably a spiral galaxy. NGC 5128 appears in the optical spectrum as a fairly large elliptical galaxy with a prominent dust lane. Its overall magnitude is 7.0 and it has been seen under perfect conditions with the naked eye, making it one of the most distant objects visible to the unaided observer. In equatorial and southern latitudes, it is easily found by star hopping from Omega Centauri. In small telescopes, the dust lane is not visible; it begins to appear with about 4 inches of aperture under good conditions. In large amateur instruments, above about 12 inches in aperture, the dust lane's west-northwest to east-southeast direction is easily discerned. Another dim dust lane on the east side of the 12-arcminute-by-15-arcminute galaxy is also visible. ESO 270-17, also called the Fourcade-Figueroa Object, is a low-surface brightness object believed to be the remnants of a galaxy; it does not have a core and is very difficult to observe with an amateur telescope. It measures 7 arcminutes by 1 arcminute. It likely originated as a spiral galaxy and underwent a catastrophic gravitational interaction with Centaurus A around 500 million years ago, stopping its rotation and destroying its structure.
NGC 4650A is a polar-ring galaxy located at a distance of 136 million light-years from Earth (redshift 0.01). It has a central core made of older stars that resembles an elliptical galaxy, and an outer ring of young stars that orbits around the core. The plane of the outer ring is distorted, which suggests that NGC 4650A is the result of a galaxy collision about a billion years ago. This galaxy has also been cited in studies of dark matter, because the stars in the outer ring orbit too quickly for their collective mass. This suggests that the galaxy is surrounded by a dark matter halo, which provides the necessary mass.
One of the closest galaxy clusters to Earth is the Centaurus Cluster, located at a distance of 160 million light-years (redshift 0.0114). It has a cooler, denser central region of gas and a hotter, more diffuse outer region. The intracluster medium in the Centaurus Cluster has a high concentration of metals (elements heavier than helium) due to a large number of supernovae. This cluster also possesses a plume of gas whose origin is unknown.
While Centaurus now has a high southern latitude, at the dawn of civilization it was an equatorial constellation. Precession has been slowly shifting it southward for millennia, and it is now close to its maximal southern declination. Thousands of years from now Centaurus will, once again, be at lower latitudes and be visible worldwide.
The figure of Centaurus can be traced back to a Babylonian constellation known as the Bison-man (MUL.GUD.ALIM). This being was depicted in two major forms: firstly, as a 4-legged bison with a human head, and secondly, as a being with a man's head and torso attached to the rear legs and tail of a bull or bison. It has been closely associated with the Sun god Utu-Shamash from very early times.
The Greeks depicted the constellation as a centaur and gave it its current name. It was mentioned by Eudoxus in the 4th century BC and Aratus in the 3rd century BC. In the 2nd century AD, Claudius Ptolemy catalogued 37 stars in Centaurus, including Alpha Centauri. Large as it is now, in earlier times it was even larger, as the constellation Lupus was treated as an asterism within Centaurus, portrayed in illustrations as an unspecified animal either in the centaur's grasp or impaled on its spear. The Southern Cross, which is now regarded as a separate constellation, was treated by the ancients as a mere asterism formed of the stars composing the centaur's legs. Additionally, what is now the minor constellation Circinus was treated as undefined stars under the centaur's front hooves.
According to the Roman poet Ovid (Fasti v.379), the constellation honors the centaur Chiron, who was tutor to many of the earlier Greek heroes including Heracles (Hercules), Theseus, and Jason, the leader of the Argonauts. It is not to be confused with the more warlike centaur represented by the zodiacal constellation Sagittarius. The legend associated with Chiron says that he was accidentally poisoned with an arrow shot by Hercules, and was subsequently placed in the heavens.
In Chinese astronomy, the stars of Centaurus are found in three areas: the Azure Dragon of the East (東方青龍, Dōng Fāng Qīng Lóng), the Vermillion Bird of the South (南方朱雀, Nán Fāng Zhū Què), and the Southern Asterisms (近南極星區, Jìnnánjíxīngōu). Not all of the stars of Centaurus can be seen from China, and the unseen stars were classified among the Southern Asterisms by Xu Guangqi, based on his study of western star charts. However, most of the brightest stars of Centaurus, including α Centauri, θ Centauri (or Menkent), ε Centauri and η Centauri, can be seen in the Chinese sky.
Some Polynesian peoples considered the stars of Centaurus to be a constellation as well. On Pukapuka, Centaurus had two names: Na Mata-o-te-tokolua and Na Lua-mata-o-Wua-ma-Velo. In Tonga, the constellation was called by four names: O-nga-tangata, Tautanga-ufi, Mamangi-Halahu, and Mau-kuo-mau. Alpha and Beta Centauri were not named specifically by the people of Pukapuka or Tonga, but they were named by the people of Hawaii and the Tuamotus. In Hawaii, the name for Alpha Centauri was either Melemele or Ka Maile-hope and the name for Beta Centauri was either Polapola or Ka Maile-mua. In the Tuamotu islands, Alpha was called Na Kuhi and Beta was called Tere.
The Centaurus is also a name of a Mega Mall and commercial / residential complex in Islamabad, Pakistan. Construction started in 2005 and the three 41 high storey towers, the tallest structures today in Islamabad, were completed by late 2012. The shopping mall was officially opened on February 17, 2013. The Centaurus originally included a 7 star hotel, construction of which is yet to begin.
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 pc) from the Sun. It is a triple star system, consisting of three stars: α Centauri A (officially Rigil Kentaurus), α Centauri B (officially Toliman), and α Centauri C (officially Proxima Centauri).Alpha Centauri A and B are Sun-like stars (Class G and K), and together they form the binary star Alpha Centauri AB. To the naked eye, the two main components appear to be a single star with an apparent magnitude of −0.27, forming the brightest star in the southern constellation of Centaurus and the third-brightest in the night sky, outshone only by Sirius and Canopus.
Alpha Centauri A has 1.1 times the mass and 1.519 times the luminosity of the Sun, while Alpha Centauri B is smaller and cooler, at 0.907 times the Sun's mass and 0.445 times its luminosity. The pair orbit about a common centre with an orbital period of 79.91 years. Their elliptical orbit is eccentric, so that the distance between A and B varies from 35.6 astronomical units (AU), to that between Saturn and the Sun (11.2 AU).
Alpha Centauri C, or Proxima Centauri, is a small and 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 light-years (1.30 pc), slightly closer than Alpha Centauri AB. Currently, the distance between Proxima Centauri and Alpha Centauri AB is about 13,000 astronomical units (0.21 ly), equivalent to about 430 times the radius of Neptune's orbit. Proxima Centauri b is an Earth-sized exoplanet in the habitable zone of Proxima Centauri; it was discovered in 2016.Bristol Centaurus
The Centaurus was the final development of the Bristol Engine Company's series of sleeve valve radial aircraft engines. The Centaurus is an 18-cylinder, two-row design that eventually delivered over 3,000 hp (2,200 kW). The engine was introduced into service late in the Second World War and was one of the most powerful aircraft piston engines to see service. The Royal Navy Historic Flight operates a Hawker Sea Fury, powered by a Bristol Centaurus engine.Centaurus A
Centaurus A or NGC 5128 is a galaxy in the constellation of Centaurus. It was discovered in 1826 by Scottish astronomer James Dunlop from his home in Parramatta, in New South Wales, Australia. There is considerable debate in the literature regarding the galaxy's fundamental properties such as its Hubble type (lenticular galaxy or a giant elliptical galaxy) and distance (10–16 million light-years). NGC 5128 is one of the closest radio galaxies to Earth, so its active galactic nucleus has been extensively studied by professional astronomers. The galaxy is also the fifth-brightest in the sky, making it an ideal amateur astronomy target, although the galaxy is only visible from low northern latitudes and the southern hemisphere.
The center of the galaxy contains a supermassive black hole with a mass equivalent to 55 million solar masses, which ejects a relativistic jet that is responsible for emissions in the X-ray and radio wavelengths. By taking radio observations of the jet separated by a decade, astronomers have determined that the inner parts of the jet are moving at about half of the speed of light. X-rays are produced farther out as the jet collides with surrounding gases resulting in the creation of highly energetic particles. The X-ray jets of Centaurus A are thousands of light-years long, while the radio jets are over a million light-years long.Like other starburst galaxies, a collision is suspected to be responsible for the intense burst of star formation. Models have suggested that Centaurus A was a large elliptical galaxy that collided and merged with a smaller spiral galaxy.Centaurus X-3
Centaurus X-3 (4U 1118-60) is an X-ray pulsar with a period of 4.84 seconds. It was the first X-ray pulsar to be discovered, and the third X-ray source to be discovered in the constellation Centaurus. The system consists of a neutron star orbiting a massive, O-type supergiant star dubbed Krzeminski's star after its discoverer, Wojciech Krzemiński. Matter is being accreted from the star onto the neutron star, resulting in X-ray emission.Chi Centauri
Chi Centauri (χ Cen, χ Centauri) is a star in the constellation Centaurus.
χ Centauri is a blue-white B-type main sequence dwarf with a mean apparent magnitude of +4.36. It is approximately 510 light years from Earth. It is classified as a Beta Cephei type variable star and its brightness varies by 0.02 magnitudes with a period of 50.40 minutes.
This star is a proper motion member of the Upper-Centaurus Lupus sub-group in the
Scorpius-Centaurus OB association,
the nearest such co-moving association of massive stars to the Sun.Lupus (constellation)
Lupus is a constellation located in the deep Southern Sky. Its name is Latin for wolf. Lupus was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations, although it was previously an asterism associated with the neighboring constellation Centaurus.NGC 4603
NGC 4603 is a spiral galaxy located about 107 million light years away in the constellation Centaurus. It is a member of the Centaurus Cluster of galaxies, belonging to the section designated "Cen30". The morphological classification is SA(s)c, which indicates it is a pure spiral galaxy with relatively loosely wound arms.During 1999, this galaxy was the subject of an extended study using the Hubble Space Telescope to locate Cepheid variable stars. A total of 43±7 were found, and the measurement of their periodicity gave a net distance estimate of 108.7+5.5−4.9 Mly (33.3+1.7−1.5 Mpc). This is consistent with the distance estimate determined through redshift measurements. As of the time of this study, NGC 4603 was the most distant galaxy for which a distance estimate had been made using Cepheid variable.On May 21, 2008, supernova SN 2008cn was discovered at a position 23.″2 north and 4.″7 east of the galaxy center. It was determined to be a high-luminosity Type II-P supernova, with a progenitor tentatively identified as a red supergiant with 15 ± 2 solar masses. Based upon the yellowish color, it may have been a member of a binary star system.NGC 4622
NGC 4622 is a face-on unbarred spiral galaxy with a very prominent ring structure located in the constellation Centaurus. The galaxy is a member of the Centaurus Cluster.NGC 4683
NGC 4683 is a barred lenticular galaxy located about 170 million light-years away in the constellation Centaurus. It was discovered by astronomer John Herschel on June 8, 1834. NGC 4683 is a member of the Centaurus Cluster.NGC 4696
NGC 4696 is an elliptical galaxy. It lies around 145,000,000 light-years (44,000,000 pc) away in the constellation Centaurus. It is the brightest galaxy in the Centaurus Cluster, a large, rich cluster of galaxies in the constellation of the same name. The galaxy is surrounded by many dwarf elliptical galaxies also located within the cluster. There is believed to be a supermassive black hole at the center of the galaxy.NGC 4706
NGC 4706 is a lenticular galaxy located about 157 million light-years away in the constellation Centaurus. It was discovered by astronomer John Herschel on June 5, 1834. NGC 4706 is a member of the Centaurus Cluster.NGC 4709
NGC 4709 is an elliptical galaxy located in the constellation Centaurus. It is considered to be a member of the Centaurus Cluster and is the dominant member of a small group of galaxies known as "Cen 45" which is currently merging with the main Centaurus Cluster (Cen 30) even though the two subclusters' line of sight redshift velocities differ by about 1500 km/s. NGC 4709 was discovered by astronomer James Dunlop on May 7, 1826.NGC 4729
NGC 4729 is an elliptical galaxy located about 160 million light-years away in the constellation Centaurus. NGC 4729 was discovered by astronomer John Herschel on June 8, 1834 and is a member of the Centaurus Cluster.NGC 4730
NGC 4730 is a lenticular galaxy located about 160 million light-years away in the constellation Centaurus. NGC 4730 was discovered by astronomer John Herschel on June 8, 1834. NGC 4730 is a member of the Centaurus Cluster.NGC 4743
NGC 4743 is a lenticular galaxy located about 145 million light-years away in the constellation Centaurus. NGC 4743 was discovered by astronomer John Herschel on June 8, 1834. It is a member of the Centaurus Cluster.NGC 4744
NGC 4744 is a barred lenticular galaxy located about 160 million light-years away in the constellation Centaurus. NGC 4744 was discovered by astronomer John Herschel on June 8, 1834. It is a member of the Centaurus Cluster.NGC 4945
NGC 4945 is a barred spiral galaxy in the constellation Centaurus, visible near the star Xi Centauri. The galaxy was discovered by James Dunlop in 1826 and is thought to be similar to the Milky Way Galaxy, although X-ray observations show that NGC 4945 has an unusual energetic Seyfert 2 nucleus that might house a supermassive black hole. This object has an estimated mass of 1.4+1.4−0.7×106 M☉.NGC 4976
NGC 4976 is a peculiar elliptical galaxy in the constellation Centaurus. It was detected with a 5" telescope working at 20x magnification by comet hunter Jack Bennett.Nova Centauri 2013
Nova Cen 2013 or V1369 Cen (PNV J13544700-5909080) was a bright nova in the constellation Centaurus. It was discovered on December 2, 2013 by amateur astronomer John Seach in Australia with a magnitude of 5.5.
On December 14, 2013 it peaked at about magnitude 3.3, making it the brightest nova so far of this millennium.Nova Centauri 2013 was observed emitting gamma-rays between 7–10 December 2013 by the Fermi Gamma-ray Space Telescope. The nova continued to brighten in gamma-rays and the peak coincided with the second optical maximum on 11 December 2013.The Swift Gamma-Ray Burst Mission detected X-ray emission from Nova Centauri 2013 on 18 and 25 February 2014 and 8 March 2014.In July 2015 it was announced that lithium has been detected in material ejected from Nova Centauri 2013. This is the first time lithium has been detected in a nova system. The amount detected was less than a billionth of the mass of the Sun. This finding is significant because it supports a theory that the extra lithium found in Population I stars (compared to Population II stars) comes from novae.