Auriga (constellation)

Auriga is a constellation in the northern sky. Its name is Latin for 'charioteer' and its stars form a shape that has been associated with the pointed helmet of a charioteer. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains among the 88 modern constellations today. Its brightest star is Capella.

Notable features

Stars

ε Aurigae and ζ Aurigae are peculiar binary stars. The orbital period of ε Aurigae is approximately 27 years, with an eclipse duration of about 18 months. The visible companion is a bright, older star (previously thought to be a bright F-class supergiant). The type of the other star is not known. ζ Aurigae has a period of 970 days, the primary is a K-class supergiant and the secondary is a B-class main sequence star. Both these systems present a rare stage of binary evolution, as the components are in a short and active evolutionary stage.

Named stars

Deep-sky objects

The galactic anticenter is located about 3.5° to the east of β Aurigae. This marks the point on the celestial sphere opposite the location of the galactic core; hence, this region marks a less extensive and less luminous part of the dust band that forms the spiral arms of the Milky Way.^[2]

Auriga has many open clusters and other objects because the Milky Way runs through it. The three brightest open clusters are M36, M37 and M38, all of which are visible in binoculars or a small telescope in suburban skies. A larger telescope resolves individual stars. The clusters are about 4100, 4400, and 4200 light years distant, respectively. Their apparent visual magnitudes are 6.3, 6.2, and 7.4, respectively.

Three other open clusters are NGC 2281, lying close to ψ⁷ Aurigae, NGC 1664, which is close to ε Aurigae, and IC 410 (or NGC 1893), a cluster with nebulosity next to IC 405, the Flaming Star Nebula, found about mid-way between M38 and ι Aurigae. AE Aurigae, a runaway star, is a bright variable star currently located within the Flaming Star Nebula.

Mythology

In Greek mythology, Auriga is identified as the mythological Greek hero Erichthonius of Athens, the chthonic son of Hephaestus who was raised by the goddess Athena. According to the anonymous writer of the composition Catasterisimi, Erichthonius was generally credited to be the inventor of the quadriga, the four-horse chariot, which he used in the battle against the usurper Amphictyon, the event that made Erichthonius the king of Athens. Erichthonius then dedicated himself to Athena and soon after, Zeus raised the Athenian hero into the night sky in honor of his ingenuity and heroic deeds^[3]

Capella is associated with the mythological she-goat Amalthea. It forms an asterism with the stars ζ Aurigae and η Aurigae, which are known as the Haedi (the Kids).

Visualizations

Traditionally, illustrations of Auriga represent it as a chariot and its driver. The driver is often represented as a shepherd, usually with a goat flung over his left shoulder (due to the resemblance of that area to a lump), with two kids (represented by the two bright stars of that name) nearby.

H.A. Rey has suggested an alternative way to connect the stars, which graphically shows the charioteer's head wearing a pointy cap and facing towards Perseus. Stars α Aur (Capella), β Aur, θ Aur, ι Aur, and ε Aur form the charioteer's head: with α Aur being of magnitude zero, β Aur being of magnitude two, and the rest of the stars being of magnitude three. Star α Aur may be taken to represent the charioteer's eye, whereas star ι Aur represents the charioteer's chin. Stars β Aur, δ Aur, and α Aur form the charioteer's pointy cap, with δ Aur being the top of the cap. Finally, the stars α Aur, ε Aur, ζ Aur, and η Aur form the charioteer's nose: η Aur being of the third magnitude.

Equivalents

For Sumerians, most part of Auriga was called Gamlu, "the Hook". In Chinese astronomy, the stars of Auriga are located among three areas: the Purple Forbidden enclosure (紫微垣, Zǐ Wēi Yuán), the White Tiger of the West (西方白虎, Xī Fāng Bái Hǔ), and the Vermilion Bird of the South (南方朱雀, Nán Fāng Zhū Què).

See also

• Psi Aurigae
• Telescopium Herschelii
• Auriga (Chinese astronomy)
• HD 30453

References

• H. A. Rey, . Enlarged World-Wide Edition. Houghton Mifflin, Boston, 1997. ISBN 0-395-24830-2.
• Ian Ridpath and Wil Tirion (2007). Stars and Planets Guide, Collins, London. ISBN 978-0007251209. Princeton University Press, Princeton. ISBN 978-0691135564.
• Richard Hinckley Allen, Star Names: Their Lore and Meaning, New York, Dover.

External links

• The Deep Photographic Guide to the Constellations: Auriga
• The clickable Auriga
• WIKISKY.ORG: Auriga
• Star Tales – Auriga

Coordinates: 06^h 00^m 00^s, +40° 00′ 00″