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86-497: 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

172-419: 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

258-416: A to avoid confusion with α ). However, a number of stars in southern constellations have uppercase letter designations, like B Centauri and G Scorpii . These letters were assigned by later astronomers, notably Lacaille in his Coelum Australe Stelliferum and Gould in his Uranometria Argentina . Lacaille followed Bayer's use of Greek letters, but this was insufficient for many constellations. He used first

344-491: 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

430-487: 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

516-491: A different constellation. Bayer's Gamma and Omicron Scorpii, for example, were later reassigned from Scorpius to Libra and given the new names Sigma and Upsilon Librae . (To add to the confusion, the star now known as Omicron Scorpii was not named by Bayer but was assigned the designation o Scorpii (Latin lowercase 'o') by Lacaille—which later astronomers misinterpreted as omicron once Bayer's omicron had been reassigned to Libra.) A few stars no longer lie (according to

602-426: 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 . In a little over 7000 years it will be at maximum visibility for those in the northern hemisphere, visible at times in the year up to quite a high northern latitude. The figure of Centaurus can be traced back to

688-437: 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

774-516: A letter to the monarch describing his observations of the southern sky, which included a rather crude map of the stars around the south celestial pole including the Southern Cross and the two Magellanic Clouds seen in an external orientation, as on a globe. Emery Molyneux and Petrus Plancius have also been cited as the first uranographers (sky mappers) to distinguish Crux as a separate constellation; their representations date from 1592,

860-567: A line from γ to α Crucis (the foot of the crucifix) approximately 4 + 1 ⁄ 2 times beyond gives a point close to the Southern Celestial Pole which is also, coincidentally, where intersects a perpendicular line taken southwards from the east–west axis of Alpha Centauri to Beta Centauri , which are stars at an alike declination to Crux and of a similar width as the cross, but higher magnitude. Argentine gauchos are documented as using Crux for night orientation in

946-443: A low mass T Tauri star is found in the constellation Centaurus. In July 2018 astronomers captured the first conclusive image of a protoplanetary disk 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 , 17,000 light-years away with a diameter of 150 light-years. It is the largest and brightest globular cluster in

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1032-582: A lowercase Greek letter (alpha (α), beta (β), gamma (γ), etc.) or a Latin letter (A, b, c, etc.) to each star he catalogued, combined with the Latin name of the star's parent constellation in genitive (possessive) form. The constellation name is frequently abbreviated to a standard three-letter form. For example, Aldebaran in the constellation Taurus (the Bull) is designated α Tauri (abbreviated α Tau , pronounced Alpha Tauri ), which means "Alpha of

1118-527: 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)

1204-611: A planet— HD 106906 b —that has one of the widest orbits of any currently known planetary-mass companions. Crux is backlit by the multitude of stars of the Scutum-Crux Arm (more commonly called the Scutum-Centaurus Arm ) of the Milky Way. This is the main inner arm in the local radial quarter of the galaxy. Part-obscuring this is: A key feature of the Scutum-Crux Arm is: The most prominent feature of Crux

1290-715: A specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. The brighter stars were assigned their first systematic names by the German astronomer Johann Bayer in 1603, in his star atlas Uranometria . Bayer catalogued only a few stars too far south to be seen from Germany, but later astronomers (including Nicolas-Louis de Lacaille and Benjamin Apthorp Gould ) supplemented Bayer's catalog with entries for southern constellations. Bayer assigned

1376-416: 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 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

1462-434: 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,

1548-424: 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 away. 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

1634-414: Is a triple star system composed of a binary system orbited by Proxima Centauri, currently the nearest star to the Sun. Traditionally called Rigil Kentaurus (from Arabic رجل قنطورس, meaning "foot of the centaur") or Toliman (from Arabic الظليمين meaning "two male ostriches"), 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;

1720-805: Is a major rail terminal in Melbourne, Australia. The Personal Ordinariate of Our Lady of the Southern Cross is a personal ordinariate of the Roman Catholic Church primarily within the territory of the Australian Catholic Bishops Conference for groups of Anglicans who desire full communion with the Catholic Church in Australia and Asia. The Knights of the Southern Cross (KSC) is a Catholic fraternal order throughout Australia. In India, there

1806-479: Is a story related to the creation of Trishanku Swarga (त्रिशंकु), meaning Cross (Crux), created by Sage Vishwamitra . In Chinese , 十字架 ( Shí Zì Jià ), meaning Cross , refers to an asterism consisting of γ Crucis, α Crucis , β Crucis and δ Crucis . In Australian Aboriginal astronomy , Crux and the Coalsack mark the head of the 'Emu in the Sky' (which is seen in the dark spaces rather than in

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1892-399: Is also called bintoéng sallatang meaning "southern star". Two United States Navy ships, USS  Centaurus  (AKA-17) and USS  Centaurus  (AK-264) , were named after Centaurus, the constellation. Crux Crux ( / k r ʌ k s / ) is a constellation of the southern sky that is centred on four bright stars in a cross -shaped asterism commonly known as

1978-579: Is also mentioned in the Samoan National Anthem . " Vaai 'i na fetu o lo'u a agiagia ai: Le faailoga lea o Iesu, na maliu ai mo Samoa. " ("Look at those stars that are waving on it: This is the symbol of Jesus, who died on it for Samoa.") The 1952-53 NBC Television Series Victory At Sea contained a musical number entitled "Beneath the Southern Cross". " Southern Cross " is a single released by Crosby, Stills and Nash in 1981. It reached #18 on Billboard Hot 100 in late 1982. "The Sign of

2064-601: Is also shared by an archaic name of the constellation in Vietnam , where it was once known as sao Cá Liệt (the ponyfish star). Among Filipino people , the southern cross have various names pertaining to tops , including kasing ( Visayan languages ), paglong ( Bikol ), and pasil ( Tagalog ). It is also called butiti ( puffer fish ) in Waray . The Javanese people of Indonesia called this constellation Gubug pèncèng ("raking hut") or lumbung ("the granary"), because

2150-486: Is also visible near the horizon from tropical latitudes of the northern hemisphere for a few hours every night during the northern winter and spring. For instance, it is visible from Cancun or any other place at latitude 25° N or less at around 10 pm at the end of April. There are 5 main stars. Due to precession , Crux will move closer to the South Pole in the next millennia, up to 67 degrees south declination for

2236-571: 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

2322-527: 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 ,

2408-511: Is of magnitude 4.0 and has a modest separation, appearing only under intense magnification due to its distance. The northerly star Theta Centauri , officially named Menkent, is an orange giant star of magnitude 2.06. It is the only bright star of Centaurus that is easily visible from mid-northern latitudes. The next bright object is Gamma Centauri , a binary star 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

2494-564: Is the Centaurus Cluster at c. 160 million light-years away, having 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

2580-496: Is the distinctive asterism known as the Southern Cross. It has great significance in the cultures of the southern hemisphere, particularly of Australia, Brazil, Chile and New Zealand. Several southern countries and organisations have traditionally used Crux as a national or distinctive symbol. The four or five brightest stars of Crux appear, heraldically standardised in various ways, on the flags of Australia , Brazil , New Zealand , Papua New Guinea and Samoa . They also appear on

2666-541: Is the most southerly member of the constellation and, at magnitude 0.8, the brightest. The three other stars of the cross appear clockwise and in order of lessening magnitude: β Crucis (Mimosa), γ Crucis (Gacrux), and δ Crucis (Imai). ε Crucis (Ginan) also lies within the cross asterism. Many of these brighter stars are members of the Scorpius–Centaurus association , a large but loose group of hot blue-white stars that appear to share common origins and motion across

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2752-555: The Ancient Greeks , where Ptolemy regarded them as part of the constellation Centaurus . They were entirely visible as far north as Britain in the fourth millennium BC. However, the precession of the equinoxes gradually lowered the stars below the European horizon, and they were eventually forgotten by the inhabitants of northern latitudes. By 400  AD , the stars in the constellation now called Crux never rose above

2838-570: The Brazilian coat of arms and, as of July 2015 , on the cover of Brazilian passports . Five stars appear in the logo of the Brazilian football team Cruzeiro Esporte Clube and in the insignia of the Order of the Southern Cross , and the cross has featured as name of the Brazilian currency (the cruzeiro from 1942 to 1986 and again from 1990 to 1994). All coins of the current (1998) series of

2924-535: The Brazilian real display the constellation. Songs and literature reference the Southern Cross, including the Argentine epic poem Martín Fierro . The Argentinian singer Charly García says that he is "from the Southern Cross" in the song "No voy en tren". The Cross gets a mention in the lyrics of the Brazilian National Anthem (1909): " A imagem do Cruzeiro resplandece " ("the image of

3010-606: The German East Africa Company of 1885–1920, which included a constellation of five white five-pointed Crux "stars" on a red ground, later served as the model for symbolism associated with generic German colonial-oriented organisations: the Reichskolonialbund of 1936–1943 and the Friends of the former German Protectorates  [ de ] (1956/1983 to the present). Southern Cross station

3096-459: 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 one of two only globular clusters to be designated with a Bayer letter ;

3182-532: The Pampas and Patagonia . Alpha and Beta Centauri are of similar declinations (thus distance from the pole) and are often referred as the "Southern Pointers" or just "The Pointers", allowing people to easily identify the Southern Cross, the constellation of Crux. Very few bright stars lie between Crux and the pole itself, although the constellation Musca is fairly easily recognised immediately south of Crux. Down to apparent magnitude +2.5 are 92 stars that shine

3268-677: The Scorpius–Centaurus association , the nearest OB association to the Sun . They are among the highest-mass stellar members of the Lower Centaurus–Crux subgroup of the association, with ages of roughly 10 to 20 million years. Other members include the blue-white stars Zeta , Lambda and both the components of the visual double star , Mu . Crux contains many variable stars . It boasts four Cepheid variables that may all reach naked eye visibility. Other well studied variable stars includes: The star HD 106906 has been found to have

3354-663: The Solomon Islands saw several figures in the Southern Cross. These included a knee protector and a net used to catch Palolo worms . Neighboring peoples in the Marshall Islands saw these stars as a fish. Peninsular Malays also see the likeness of a fish in the Crux, particularly the Scomberomorus or its local name Tohok . Bayer letter A Bayer designation is a stellar designation in which

3440-514: The Southern Cross . It lies on the southern end of the Milky Way 's visible band. The name Crux is Latin for cross. Even though it is the smallest of all 88 modern constellations , Crux is among the most easily distinguished as its four main stars each have an apparent visual magnitude brighter than +2.8. It has attained a high level of cultural significance in many Southern Hemisphere states and nations. Blue-white α Crucis (Acrux)

3526-701: 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

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3612-560: The Australian Eureka Flag . The constellation was also used on the dark blue, shield-like patch worn by personnel of the U.S. Army's Americal Division , which was organized in the Southern Hemisphere, on the island of New Caledonia , and also on the blue diamond of the U.S. 1st Marine Division , which fought on the Southern Hemisphere islands of Guadalcanal and New Britain . The Petersflagge flag of

3698-619: The Bull". Bayer used Greek letters for the brighter stars, but the Greek alphabet has only twenty-four letters, while a single constellation may contain fifty or more stars visible to the naked eye. When the Greek letters ran out, Bayer continued with Latin letters: uppercase A , followed by lowercase b through z (omitting j and v , but o was included), for a total of another 24 letters. Bayer did not label "permanent" stars with uppercase letters (except for A , which he used instead of

3784-497: 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

3870-788: The Cross shines"). The Southern Cross is mentioned in the Australian National Anthem , " Beneath our radiant Southern Cross we'll toil with hearts and hands " The Southern Cross features in the coat of arms of William Birdwood, 1st Baron Birdwood , the British officer who commanded the Australian and New Zealand Army Corps during the Gallipoli Campaign of the First World War . The Southern Cross

3956-628: The Greek letters, Bayer sometimes used the leftover Greek letters for miscellaneous labels as well. Ptolemy designated four stars as "border stars", each shared by two constellations: Alpheratz (in Andromeda and Pegasus ), Elnath (in Taurus and Auriga ), Nu Boötis ( Nu and Nu )(in Boötes and Hercules ) and Fomalhaut (in Piscis Austrinus and Aquarius ). Bayer assigned

4042-607: The Pointers are its rope. In Tonga it is known as Toloa ("duck"); it is depicted as a duck flying south, with one of his wings ( δ Crucis ) wounded because Ongo tangata ("two men", α and β Centauri ) threw a stone at it. The Coalsack is known as Humu (the " triggerfish "), because of its shape. In Samoa the constellation is called Sumu ("triggerfish") because of its rhomboid shape, while α and β Centauri are called Luatagata (Two Men), just as they are in Tonga. The peoples of

4128-579: The Portuguese monarch. Explorer Amerigo Vespucci seems to have observed not only the Southern Cross but also the neighboring Coalsack Nebula on his second voyage in 1501–1502. Another early modern description clearly describing Crux as a separate constellation is attributed to Andrea Corsali , an Italian navigator who from 1515 to 1517 sailed to China and the East Indies in an expedition sponsored by King Manuel I . In 1516, Corsali wrote

4214-472: The Southern Cross on exiting the Gambia River in 1455, calling it the carro dell'ostro ("southern chariot"). However, Cadamosto's accompanying diagram was inaccurate. Historians generally credit João Faras for being the first European to depict it correctly. Faras sketched and described the constellation (calling it " las guardas ") in a letter written on the beaches of Brazil on 1 May 1500 to

4300-509: The Southern Cross" is a song released by Black Sabbath in 1981. The song was released on the album " Mob Rules ". The Order of the Southern Cross is a Brazilian order of chivalry awarded to "those who have rendered significant service to the Brazilian nation". In " O Sweet Saint Martin's Land ", the lyrics mention the Southern Cross: Thy Southern Cross the night . A stylized version of Crux appears on

4386-566: The Tropic of Cancer. In Cygnus , for example, Bayer's fixed stars run through g , and on this chart Bayer employs H through P as miscellaneous labels, mostly for neighboring constellations. Bayer did not intend such labels as catalog designations, but some have survived to refer to astronomical objects: P Cygni for example is still used as a designation for Nova Cyg 1600. Tycho's Star ( SN 1572 ), another "temporary star", appears as B Cassiopeiae. In charts for constellations that did not exhaust

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4472-564: The assignment of those letters to variable stars or have actually turned out to be variable. In most constellations, Bayer assigned Greek and Latin letters to stars within a constellation in rough order of apparent brightness , from brightest to dimmest. The order is not necessarily a precise labeling from brightest to dimmest: in Bayer's day stellar brightness could not be measured precisely. Instead, stars were traditionally assigned to one of six magnitude classes (the brightest to first magnitude,

4558-425: The asterism are Alpha, Beta, Gamma, and Delta Crucis. There is also a fifth star, that is often included with the Southern Cross. There are several other naked-eye stars within the borders of Crux, especially: Unusually, a total of 15 of the 23 brightest stars in Crux are spectrally blue-white B-type stars. Among the five main bright stars, Delta, and probably Alpha and Beta, are likely co-moving B-type members of

4644-569: The brightest as viewed from the Earth . Three of these stars are in Crux making it the most densely populated as to those stars (this being 3.26% of these 92 stars, and in turn being 19.2 times more than the expected 0.17% that would result on a homogenous distribution of all bright stars and a randomised drawing of all 88 constellations, given its area, 0.17% of the sky). Within the constellation's borders, there are 49 stars brighter than or equal to apparent magnitude 6.5. The four main stars that form

4730-560: The constellation, as adopted by the International Astronomical Union in 1922, is "Cru". The official constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a polygon of four segments. In the equatorial coordinate system , the right ascension coordinates of these borders lie between 11 56.13 and 12 57.45 , while the declination coordinates are between −55.68° and −64.70°. Its totality figures at least part of

4816-402: The designation "Alpha". A good example is the constellation Gemini , where Pollux is Beta Geminorum and the slightly dimmer Castor is Alpha Geminorum. In addition, Bayer did not always follow the magnitude class rule; he sometimes assigned letters to stars according to their location within a constellation, or the order of their rising, or to historical or mythological details. Occasionally

4902-434: The dimmest to sixth), and Bayer typically ordered stars within a constellation by class: all the first-magnitude stars (in some order), followed by all the second-magnitude stars, and so on. Within each magnitude class, Bayer made no attempt to arrange stars by relative brightness. As a result, the brightest star in each class did not always get listed first in Bayer's order—and the brightest star overall did not necessarily get

4988-537: 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

5074-474: 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 11 million light-years away (redshift 0.00183). It has

5160-485: The first is of magnitude −0.01 and the second: 1.35. Proxima, the tertiary star, is a red dwarf of magnitude 11.0; it appears almost 2 degrees away from the close pairing of Alpha 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 Alpha couple revolve in 80-year periodicity and will next appear closest as seen from Earth's telescopes in 2037 and 2038, together as they appear to

5246-452: The first three of these stars a Greek letter from both constellations: Alpha Andromedae = Delta Pegasi , Beta Tauri = Gamma Aurigae , and Nu Boötis = Psi Herculis . (He catalogued Fomalhaut only once, as Alpha Piscis Austrini .) When the International Astronomical Union (IAU) assigned definite boundaries to the constellations in 1930, it declared that stars and other celestial objects can belong to only one constellation. Consequently,

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5332-605: The flags of the Australian state of Victoria , the Australian Capital Territory , the Northern Territory , as well as the flag of Magallanes Region of Chile , the flag of Londrina (Brazil) and several Argentine provincial flags and emblems (for example, Tierra del Fuego and Santa Cruz ). The flag of the Mercosur trading zone displays the four brightest stars. Crux also appears on

5418-456: The former depicting it on his celestial globe and the latter in one of the small celestial maps on his large wall map. Both authors, however, depended on unreliable sources and placed Crux in the wrong position. Crux was first shown in its correct position on the celestial globes of Petrus Plancius and Jodocus Hondius in 1598 and 1600. Its stars were first catalogued separately from Centaurus by Frederick de Houtman in 1603. The constellation

5504-423: The globular cluster 47 Tucanae (Xi 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

5590-488: The handle and the four stars as the left hand of Tagai, and the stars of Musca as the trident of the fishing spear he is holding. In Aranda traditions of central Australia, the four Cross stars are the talon of an eagle and Gamma Centauri as its leg. Various peoples in the East Indies and Brazil viewed the four main stars as the body of a ray. In both Indonesia and Malaysia, it is known as Bintang Pari and Buruj Pari , respectively ("ray stars"). This aquatic theme

5676-400: The horizon throughout most of Europe. Dante may have known about the constellation in the 14th century, as he describes an asterism of four bright stars in the southern sky in his Divine Comedy . His description, however, may be allegorical, and the similarity to the constellation a coincidence. The 15th century Venetian navigator Alvise Cadamosto made note of what was probably

5762-600: The latter is usually the brighter. (Betelgeuse is a variable star and can at its maximum occasionally outshine Rigel.) Bayer then repeated the procedure for the stars of the 2nd magnitude, labeling them from gamma through zeta in "top-down" (north-to-south) order. Letters as far as Latin p were used for stars of the sixth magnitude. Although Bayer did not use uppercase Latin letters (except A ) for "fixed stars", he did use them to label other items shown on his charts, such as neighboring constellations, "temporary stars", miscellaneous astronomical objects, or reference lines like

5848-594: 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 ),

5934-591: The lowercase letters, starting with a , and if needed the uppercase letters, starting with A , thus deviating somewhat from Bayer's practice. Lacaille used the Latin alphabet three times over in the large constellation Argo Navis , once for each of the three areas that are now the constellations of Carina , Puppis and Vela . That was still insufficient for the number of stars, so he also used uppercase Latin letters such as N Velorum and Q Puppis . Lacaille assigned uppercase letters between R and Z in several constellations, but these have either been dropped to allow

6020-572: The middle of the constellation. However, by the year 14,000, Crux will be visible for most parts of Europe and the continental United States. Its visibility will extend to North Europe by the year 18,000 when it will be less than 30 degrees south declination. In the Southern Hemisphere , the Southern Cross is frequently used for navigation in much the same way that Polaris is used in the Northern Hemisphere . Projecting

6106-627: The modern constellation Carina . Norma's Alpha and Beta were reassigned to Scorpius and re-designated N and H Scorpii respectively, leaving Norma with no Alpha. Francis Baily died before designating an Alpha in Leo Minor , so it also has no Alpha. (The star 46 Leonis Minoris would have been the obvious candidate.) In Orion , Bayer first designated Betelgeuse and Rigel , the two 1st-magnitude stars (those of magnitude 1.5 or less), as Alpha and Beta from north to south, with Betelgeuse (the shoulder) coming ahead of Rigel (the foot), even though

6192-484: The modern constellation boundaries) within the constellation for which they are named. The proper motion of Rho Aquilae , for example, carried it across the boundary into Delphinus in 1992. A further complication is the use of numeric superscripts to distinguish neighboring stars that Bayer (or a later astronomer) labeled with a common letter. Usually these are double stars (mostly optical doubles rather than true binary stars ), but there are some exceptions such as

6278-422: The naked eye they present the third-brightest "star" in the night sky. One other first magnitude star Beta Centauri is in the constellation in a position beyond Proxima and toward the narrow axis of Crux, thus with Alpha forming a far-south limb of the constellation. Also called Hadar and Agena, it is a double star; the primary is a blue-hued giant star of magnitude 0.6, 525 light-years from Earth. The secondary

6364-418: The order looks quite arbitrary. Of the 88 modern constellations, there are at least 30 in which Alpha is not the brightest star, and four of those lack a star labeled "Alpha" altogether. The constellations with no Alpha-designated star include Vela and Puppis —both formerly part of Argo Navis , whose Greek-letter stars were split among three constellations. Canopus , the former α Argus, is now α Carinae in

6450-417: 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

6536-633: The patterns of stars) in several Aboriginal cultures , while Crux itself is said to be a possum sitting in a tree ( Boorong people of the Wimmera region of northwestern Victoria), a representation of the sky deity Mirrabooka ( Quandamooka people of Stradbroke Island ), a stingray ( Yolngu people of Arnhem Land ), or an eagle ( Kaurna people of the Adelaide Plains ). Two Pacific constellations also included Gamma Centauri . Torres Strait Islanders in modern-day Australia saw Gamma Centauri as

6622-556: 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 Pointer (α Centauri and β Centauri) is one of the asterisms used by Bugis sailors for navigation, called bintoéng balué , meaning "the widowed-before-marriage". It

6708-466: The redundant second designation in each pair above has dropped out of use. Bayer assigned two stars duplicate names by mistake: Xi Arietis (duplicated as Psi Ceti ) and Kappa Ceti ( Kappa and Kappa ) (duplicated as g Tauri ). He corrected these in a later atlas, and the duplicate names were no longer used. Other cases of multiple Bayer designations arose when stars named by Bayer in one constellation were transferred by later astronomers to

6794-506: 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

6880-426: The shape of the constellation was like that of a raking hut . The Southern Cross ( α , β , γ and δ Crucis ) together with μ Crucis is one of the asterisms used by Bugis sailors for navigation, called bintoéng bola képpang , meaning "incomplete house star" The Māori name for the Southern Cross is Māhutonga and it is thought of as the anchor ( Te Punga ) of Tama-rereti's waka (the Milky Way ), while

6966-494: The sky. Crux is sometimes confused with the nearby False Cross asterism by stargazers. The False Cross consists of stars in Carina and Vela, is larger and dimmer, does not have a fifth star, and lacks the two prominent nearby "Pointer Stars". Between the two is the even larger and dimmer Diamond Cross . Crux is easily visible from the southern hemisphere , south of 35th parallel at practically any time of year as circumpolar. It

7052-591: The southern Milky Way. Crux contains four Cepheid variables , each visible to the naked eye under optimum conditions. Crux also contains the bright and colourful open cluster known as the Jewel Box (NGC 4755) on its eastern border. Nearby to the southeast is a large dark nebula spanning 7° by 5° known as the Coalsack Nebula , portions of which are mapped in the neighbouring constellations of Centaurus and Musca . The bright stars in Crux were known to

7138-400: The year south of the 25th parallel north . In tropical regions Crux can be seen in the sky from April to June. Crux is exactly opposite to Cassiopeia on the celestial sphere, and therefore it cannot appear in the sky with the latter at the same time. In this era, south of Cape Town , Adelaide , and Buenos Aires (the 34th parallel south ), Crux is circumpolar and thus always appears in

7224-473: 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

7310-479: Was later adopted by Jakob Bartsch in 1624 and Augustin Royer in 1679. Royer is sometimes wrongly cited as initially distinguishing Crux. Crux is bordered by the constellations Centaurus (which surrounds it on three sides) on the east, north and west, and Musca to the south. Covering 68 square degrees and 0.165% of the night sky, it is the smallest of the 88 constellations. The three-letter abbreviation for

7396-454: 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

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