A large rich and splendid constellation representing a Centaur who in Greek mythology represented the scholarly centaur Chiron who was then tutor to many of the Greek heroes. He was placed in the sky after accidentality being struck by a poisoned arrow shot by Hercules.
Sadly, from Britain hardly any of Centaurus is above the
horizon although it is true that from the south coast on a very clear night it
might just be possible to see the stars iota and theta, but they cannot be seen
from the north of England.
Some of the Centaur’s stars and some also from Lupus the
Wolf were known to the early Arab astronomers as Al Kadb al Karm, the Vine
Branch. There again it is sometimes referred to by the Arabs as Al Shamarih,
The Broken off Palm Branches which were loaded with dates which the Arab
astronomer Al Kazwini described as being held out in the centaur’s hand.
The brightest star is Alpha or Rigil Kentaurus which means ‘Foot of the Centaur’ shines with a magnitude of 0.0 is the 4.37 light years from Earth. Its name which appears to have been given to the star by the Arab astronomer Ulug Beg is not always used and the star is simply referred to as alpha Centaurus. However, another Arabic name for the star is Hadar which means Ground.
Alpha is composed of three stars A, B, and C. It is one of the finest binary stars in the
sky which was discovered in 1689 by Father Richaud at Pondicherry in India. The
A component is a G class star slightly hotter than the Sun with the B component
being K class star cooler than the Sun, they orbit each other every 80 years.
However, it is C component or to give its name Proxima that
is the closest star to us being a mere 4.24 light years or around
24,000,000,000,000 million miles away. It takes over 200,000 years to orbit the
A and B stars, Scottish astronomer Robert T. A. Innes discovered Proxima in
1915. It is a small red dwarf and has planets that orbit it.
Beta is often called Agena and it does not appear to have
any known meaning. The Arab astronomer however called it Wazn which means
Weight. To the Chinese it was known as Mah Fuh or The Horse’s Belly. It’s a B
class star much hotter than the Sun and it is 390 light years away.
Alpha and beta are known as the Southern Pointers as they
point the way to the Southern Cross. The bushmen of South Africa knew the two
stars as Two Men That Once Were Lions; and the Australian Aboriginals knew them
as Two Brothers who speared Tchingal a killer emu to death.
Theta or to the Arab astronomers Mankib which means shoulder
is often known today as Menkent or again shoulder. The star has a magnitude of
2.1 is the fourth brightest star in the constellation. Theta is the 8th
letter of the Greek alphabet it should have the letter delta as it is the
fourth brightest letter. The star is 59 light years away and is a K class giant
star indicating it is cooler than our Sun.
There does not appear to be a name for the star gamma it has
a magnitude on 2.2, it’s an A class star
hotter than the Sun and is 130 light years away.
Centaurus has a rich selection of over 200 clusters and
galaxies far too many to mention so I will just stick with the most obvious one
and that is Omega Centauri or NGC 5139 which
is the largest and brightest globular cluster in the sky, it is so bright it
can be seen with the naked eye that. It was first catalogued in 150 CE by
Ptolemy and it was Bayer in 1603 who gave it the Greek letter omega. Neither
realised that it was not a star but a cluster of stars. It appears as a
magnitude 3.7 ‘star’. It is 15,800 light years away and has a diameter of 150
light years and contains around 10 million stars.
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