Auriga - The Charioteer

Auriga is situated along the northern Milky Way, and appears as a slightly irregular pentagon north of Taurus, and between Perseus and Gemini. Best seen from October through April, it is a large fall and winter constellation in the northern hemisphere. For those living at far northern latitudes, Auriga can be seen much of the year.

History and Mythology

Auriga, the Charioteer, has been known from ancient times, and was one of the first constellation to be named. Auriga is usually shown as a man holding reins without horses or a chariot. The charioteer is identified as either Hephaestus, the Roman god Vulcan, or his son, Erechtheus. Erechtheus is claimed by the Greeks to have invented the chariot.

Auriga is portrayed with a goat over one shoulder. The bright star Capella marks Auriga's left shoulder. The three small stars above Capella are known as the Kids. Capella's name derives from the Latin meaning "little she-goat". The star Capella was said to be the goat Amalthea, the goat that nursed the infant Zeus. While playing with her, Zeus accidentally broke off one of Amalthea's horns. He gave the horn the magical power to provide unlimited amounts of food and drink to anyone who asked. It became the cornucopia, and was forever filled with the fruits of the Earth.

Capella was the Patron Star of Babylon, and in India is the heart of Brahma. To the Arabs, it is the overseer of the celestial game in which the other stars are the players.

Notable Stars

Capella is a brilliant star, almost as bright as Vega, and the 6th brightest star in the sky. Capella rises along the northeastern horizon in late summer, and is thus known as the Harvest Star. Capella marks the rising of the winter constellations Taurus and Orion. It is the closest first magnitude star to the North Celestial Pole, making it important for navigation, because from mid-northern latitudes it is visible for at least some part of the night every month of the year. Capella is a relatively nearby star, about 42 light years away, and is actually a close double star system, consisting of two G-type giant stars with a similar surface temperature to our Sun's, but luminosities 50 and 80 times greater.

Menkalinan (Arabic for shoulder of the charioteer) is a variable star, with a magnitude range of 1.9 to 2.0. It is an eclipsing binary system, where two stars in orbit periodically eclipse one another.

The supergiant Epsilon Aurigae is also an eclipsing binary star, but with a period of more than 27 years! At a distance of more than 2,000 light-years, it is 200 times larger, and 60,000 times more luminous than our sun. It is believed to be eclipsed by a disk of dark material orbiting an unseen companion, which explains the unusual duration (more than 2 years) of the eclipses.

Clusters, Nebulae, and Galaxies

Auriga has three easily-seen Messier objects. M 36, the Pinwheel Cluster, is an open cluster of 6th magnitude, concentrated but rather irregular, containing about 60 stars. M 37 is another 6th magnitude open cluster, and is one of finest open clusters in the sky. It covers an area nearly as large as the full moon. M 38, the Starfish Cluster, is about the same size as M 37, but is somewhat fainter at 7th magnitude, containing about 100 stars.

The emission nebula IC 405, also known as the "Flaming Star Nebula", is located near (and illuminated by) the variable star AE Aurigae. It is visible in - but a challenging object for - small telescopes. AE Aurigae is a "runaway star" which is moving directly away from Mu Columbae. Both stars can be traced back to a supernova explosion in the Orion Nebula more than 2.5 million years ago, which ejected them in opposite directions at high velocities.

IC 410 is an interesting diffuse nebula. It includes a small star cluster, NGC 1893, in its central area, and it has a dark hole near the center. IC 410 resembles the Rosette Nebula in the constellation Monoceros.

Another star cluster with nebulosity worth viewing is NGC 1931 and IC 417, found just west of the open cluster M 36.