Centaurus

Centaurus ( /sɛnˈtɔrəs/) 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.

Notable features

Stars

Centaurus contains the Alpha Centauri system, a triple star system consisting of a bright binary star to which the much fainter red dwarf Proxima Centauri is gravitationally bound; Proxima is the nearest known star to the Sun.

In addition to Alpha Centauri (the 4th brightest star in the sky), a second first magnitude star, Hadar, is part of Centaurus.

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."^[1]

Deep-sky objects

ω Centauri, despite being listed as the constellation's "omega" star, is in fact a globular cluster, also classified as NGC 5139. It is the largest and brightest globular cluster in the Milky Way.

The nearby lenticular galaxy, radio source Centaurus A (NGC 5128), the elliptical galaxy ESO 325-G004, and the spiral galaxy NGC 4444 are all located in this constellation.

History

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.^[2]

The Greeks depicted the constellation as a centaur and gave it its current name. The name Centaurus in mythology is given not to a centaur but a deformed human who would later mate with mares and spawn the centaur race. It was mentioned by Eudoxus in the 4th century BCE and Aratus in the 3rd century BCE. In the 2nd century AD, Claudius Ptolemy catalogued 37 stars in Centaurus. 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. However, most authorities consider Sagittarius to be the civilized Chiron, while Centaurus represents a more uncouth member of the species.^[3]

Equivalents

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 Cen, θ Cen, ε Cen and η Cen, can be seen in the Chinese sky.

Namesakes

Two United States navy ships, USS Centaurus (AKA-17) and USS Centaurus (AK-264), are named after the constellation.

See also

• Centaurus (Chinese astronomy)
• List of brightest stars

References

• Centaurus, by Chris Dolan
• C.S. Constellations and Stars
• Constellations, by Richard Dibon-Smith
• Ian Ridpath and Wil Tirion (2007). Stars and Planets Guide, Collins, London. ISBN 978-0007251209. Princeton University Press, Princeton. ISBN 978-0691135564.

External links

• The Deep Photographic Guide to the Constellations: Centaurus
• Starry Night Photography: Centaurus
• Star Tales – Centaurus
• Centaurus Constellation

Coordinates: 13^h 00^m 00^s, −50° 00′ 00″