Auriga, The CharioteerAuriga, the Charioteer
represents Neptune himself, riding across the heavens where the hero Perseus, King Cepheus, and the other characters from the Roman myth also can be found. You will remember that it was Neptune who called up Cetus to ravage the coast in response to the insult the Sea-Nymphs received from the vain Cassiopeia. Neptune ruled the oceans as Jupiter ruled the heavens and Pluto ruled the realm of the underworld and of the dead. All three of these deities were sons of the Titan Saturn.

Some, however, say that the constellation is Erichthonius, son of Athena, who was lame and invented the four-horse chariot in order to move around more freely. The name Auriga is Latin for “charioteer.”

Or, so another story goes, the principal star of the constellation, Capella, is Amalthea, the she-goat that nursed the infant Jupiter. Capella, from the Latin for little goat, is known as the “Shepherd's Star.” From the earliest times the stars of Auriga have portrayed a charioteer holding his reins while carrying a goat and its two kids. Three small stars southwest of Capella are known today as the “Kids.”

Strangely, in China the stars of Auriga were considered the five chariots of the five emperors. These were the star gods whose thrones were in Leo and in Cepheus. The Babylonians also pictured a chariot in this part of the sky.

Capella is the northernmost of all the first-magnitude stars, the sixth brightest of all the stars. It is one of the stars of the asterism known as the Winter Oval or Hexagon, lying between Castor and Aldebaran. It is a yellow giant at a distance of 45 light years and has a luminosity 160 times that of the Sun. It is a spectroscopic binary pair, its components closer to each other than Earth is from the Sun. At a distance of a thousand AU, a pair of red dwarf stars are also a part of the Capella system.

Capella, COAST imageIn 1995, this stellar system was the first target for a new technology known as COAST, the Cambridge Optical Aperture Synthesis Telescope, a coherent array of four telescopes operating in the red and near infra-red, using Michelson interferometry on baselines of up to 100m to give images with a resolution down to 1 milliarcsecond. Other methods, such as adaptive optics, when used on existing single telescopes, have limiting resolutions no better than about 10 milliarcseconds.

Of the Kids, the star closest to Capella is Epsilon Aurigae and for a hundred-fifty years it has been one of the most observed and controversial of all the stars. It is an eclipsing binary pair, lying about 4000 light years from us. Only one of the stars is visible. When it is eclipsed by its partner every 27 years, this star remains at a diminished luminosity for a year. Several theories are proposed to explain the mystery of the facts. One suggestion is that the unseen star may be 2000 times the diameter of the Sun; another possibility is that the eclipsing body is not a star, but a vast shell of dust and gas—a prototype star. Other theories also help to keep astronomers bewildered.

Generally visualized as a large pentagon joined to El Nath, the tip of the northern horn of Taurus, the bull, Auriga boasts of four galactic clusters of stars. Three are Messier objects M36, M37 and M38. There is also NGC 1907, a smaller cluster just south of M38.

M38, M36, and M37 images
M38 (left) lies about five degrees north of El Nath, the bright star that Auriga shares with Taurus. This cluster contains about 100 stars within an area 20 minutes in diameter. It may be barely visible to the unaided eye.

Discovered in 1749, M36 (center) is a compact group of 60 stars. It can be found by looking 1.6° south and 1.5° east from M38.

Then from M36, go 1.7° south and 3.4° east to find M37 (right). This is one of the finest of all open clusters, with perhaps 150 stars down to 12th magnitude. Twelve red giants are among these stars. The cluster is about 200 million years old. This is the largest and brightest of the clusters in Auriga.

Conrad Jung's photos were taken with a CCD camera attached to his 80mm f/5 finderscope. Each image is oriented with north at the top and each exposure was about 45 seconds.

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