Star Tales – Centaurus

Centaurs were mythical beasts, half-man, half-horse. They were a wild and ill-behaved race, particularly when the wine bottle was opened. But one centaur, Chiron, stood out from the rest as being wise and scholarly, and he is the one who is represented by the constellation Centaurus.

Chiron was born of different parents from the other centaurs, which accounts for his difference in character. His father was Cronus, king of the Titans, who one day caught and seduced the sea nymph Philyra. Surprised in the act by his wife Rhea, Cronus turned himself into a horse and galloped away, leaving Philyra to bear a hybrid son.

Chiron grew up to be a skilled teacher of hunting, medicine and music; his cave on Mount Pelion became a veritable academy for young princes in search of a good education. Chiron was so trusted by the gods and heroes of ancient Greece that he was made foster-father to Jason and Achilles; but perhaps his most successful pupil was Asclepius, son of Apollo, who became the greatest of all healers and is commemorated in the constellation Ophiuchus.

Centaurus from the Uranographia of Johann Bode. The centaur holds a long pole called a thyrsus on which is impaled Lupus, the wolf. Alpha Centauri, the closest star to the Sun, marks the centaur’s forefoot while Crux, the Southern Cross, is found under his hind quarters.

For a creature who did so much good during his lifetime, Chiron suffered a tragic death. It arose from a visit paid by Heracles to the centaur Pholus, who entertained him to dinner and offered him wine from the centaurs’ communal jar. When the other centaurs realized their wine was being drunk they burst angrily into the cave, armed with rocks and trees. Heracles repulsed them with a volley of arrows. Some of the centaurs took refuge with Chiron, who had been innocent of the attack, and an arrow of Heracles accidentally struck Chiron in the knee. Heracles, concerned for the good centaur, pulled out the arrow, apologizing profusely, but he already knew that Chiron was doomed. Even Chiron’s best medicine was no match for the poison of the Hydra’s blood in which Heracles had dipped his arrows.

Aching with pain, but unable to die because he was the immortal son of Cronus, Chiron retreated to his cave. Rather than let him suffer endlessly, Zeus agreed that Chiron should transfer his immortality to Prometheus. Thus released, Chiron died and was placed among the stars. Another version of the story simply says that Heracles visited Chiron and that while the two were examining his arrows one accidentally dropped on the centaur’s foot. In the sky, the centaur is depicted as about to sacrifice an animal (the constellation Lupus) on the altar (Ara). Eratosthenes says that this is a sign of Chiron’s virtue.

Centaurus contains the closest star to the Sun, Alpha Centauri, 4.4 light years away. Alpha Centauri is also known as Rigil Kentaurus, from the Arabic meaning ‘centaur’s foot’. To the naked eye it appears as the third-brightest star in the sky, but a small telescope reveals it to be double, consisting of two yellow stars like the Sun. A third, much fainter companion star is called Proxima Centauri because it is slightly closer to us than the other two. Beta Centauri is called Hadar, from an Arabic name signifying one member of a pair of stars. Alpha and Beta Centauri mark the front legs of the centaur, and they act as pointers to Crux, the Southern Cross, which lies under the centaur’s rear quarters. Centaurus also contains the largest and brightest globular star cluster visible from Earth, Omega Centauri.