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 is included among the 88 modern constellations. 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 an
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.
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.
Named Stars
Deep sky objects
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
According to one Greek myth, Auriga represents
Hephaestus, the blacksmith god, who was lame and invented the chariot so as to easily travel wherever he wanted. In another Greek myth, Auriga is said to represent
Myrtilus, the charioteer of King
Oenomaus, and who sabotaged the king's chariot.
Auriga might also represent the 10th Labour of Hercules. Together with the area of the sky that is deserted (now the new and extremely faint constellations
Camelopardalis and
Lynx), and the other features of the area in the
Zodiac sign of
Gemini (i.e. the
Milky Way, and the constellations
Gemini,
Orion, and
Canis Major), this may be the origin of the myth of the cattle of
Geryon, which forms one of
The Twelve Labours of
Heracles.
More conventionally, Auriga is also identified as the mythological Greek hero
Erichthonius of Athens, the chthonic son of Hephaestus that was raised by the goddess
Athena. 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 that made Erichthonius the king of
Athens.
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
Auriga carrying the goat and kids depicted in , a set of constellation cards published in London c.1825
Before the
classical era, Auriga was identified as a chariot and its driver, which it can resemble when the fainter stars visible to the naked eye are acknowledged. However, the driver was considered to be a shepherd rather than a charioteer, usually one which had flung a goat over its left shoulder (due to the resemblance of that area to a lump), and had its kids (two bright stars) nearby.
Diagram of an alternate way to connect the stars of the constellation Auriga.
The stars can be connected in an alternative way, 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.
The Chinese constellation Wǔ Chē / the
Five Chariots is largely analogous to Auriga, and to the asterism of the pentagon within it.
