Auriga is a beautiful pentagonal constellation that is almost circumpolar, making it visible most of the year round from the northern hemisphere, but best seen during autumn and winter. “The Charioteer”, as it is also known, occupies 657 square degrees of the celestial sphere, making it the 21st largest constellation in the night sky. Auriga also contains the 6th brightest star in the night sky, Capella, found 42.2 light years away and shining with a magnitude of 0.08, as well as a number of fine star clusters, including M36, M37 and M38.
Auriga is a northern sky constellation that can be seen by observers located between +90° and -40° of latitude, although best visible from the northern hemisphere during the months of February and March. Located north of Orion, Auriga also seems to be attached to the northern horn of Taurus the Bull via the star once known as Gamma Aurigae, but which has since been reassigned to the constellation of Taurus as the star Beta Tauri. Neighboring constellations of Auriga includes Camelopardalis, Gemini, Lynx, Perseus, and Taurus.
Perseus Constellation Family
Auriga belongs to the Perseus family of constellations, along with Andromeda, Cassiopeia, Cepheus, Cetus, Lacerta, Pegasus, Perseus and Triangulum.
Auriga means “charioteer” in Latin, with the constellation frequently depicted as a man holding the reins of a chariot in his right hand, while carrying a she-goat and two kids in his left arm. Of the several myths associated with Auriga, the most celebrated story concerns the Athenian King Erichthonius, a son of the god Hephaestus, who was raised by Athena and taught many skills, including the art of taming, then harnessing four horses to a single chariot, a technique associated with Helios, the sun-god, who rode his four-horse chariot daily across the skies. This impressed Zeus so much that he later found a place for Erichthonius amongst the stars, and in time tradition came to acknowledge Erichthonius as the first among men to use a quadriga, or a special two-wheeled chariot drawn by four horses. However, a simpler variation on the chariot myth states that Erichthonius was lame, and so built the chariot for himself in order to travel without difficulty whenever he so desired.
Auriga is a bright constellation that is easily identified, as its distinctive pentagon shape contains one first magnitude and four second magnitude stars.
– Capella (Alpha Aurigae) is a yellow star situated 42 light-years from our solar system with a magnitude of 0.08, making it the night sky’s 6th brightness star. In fact, just Vega in the constellation Lyra, and Arcturus in Boötes are more luminous in the northern skies. However, the “Goat Star”, as Auriga is also known, is actually a multiple system whose primary components are a pair of yellow-orange giant stars in a close orbit at just 0.76 AU apart, Capella Aa and Ab, both of which have around 10 times the Sun’s diameter, and two and a half times its mass. A pair of smaller red dwarfs, Capella H and Capella L, are located around 10,000 AU away, and orbit the primary pair once every 400 years or so.
The Capella multiple system also forms part of the The Hyades Stream, a big grouping of moving stars that follow a trajectory close to that of the Hyades open star cluster in Taurus. In classical depictions, Capella forms “The Charioteer’s” left shoulder, and it represents the goat that suckled Zeus, Amalthea.
– Menkalinan (Beta Aurigae), the second brightest star in Auriga, is a triple star system found 85 light years from the Sun with a magnitude of 1.90. This figure varies from between 1.85 and 1.93, though, as its two brightest components are white subgiant stars with an orbital period of just 3.96 days, thus resulting in frequent partial eclipses of one another. The third star is a red dwarf around 330 AU away. The name Menkalinam derives from the Arabic for “the Shoulder of the Rein-holder”.
– Mahasim (Theta Aurigae), the constellation’s third brightest star, is a binary system located 173 light years away with an apparent magnitude of 2.65. Its primary component is a white dwarf star with five times our sun’s radius, three times its mass, and around 263 times its luminosity. Mahasim derives from the Arabic word for the “wrist.”
Others stars of interest in Auriga includes Kabdhilinan (Iota Aurigae, Hassaleh), an orange giant 512 light-years away of magnitude 2.69, whose name comes from the Arabic for “the ankle of the rein holder”; and Almaaz (Epsilon Aurigae), an eclipsing binary 2,000 light years distant of magnitude 2.98, whose name means “goat”. Almaaz is also contained in an asterism of three stars which form a triangle known as “The Kids”, along with Haedus I (Zeta Aurigae), and Haedus II (Eta Aurigae).
Notable Deep Sky Objects
The Milky Way runs through the constellation of Auriga, making it a rich source for deep-sky objects, with three Messiers and two nebula counted amongst is many stargazing attractions.
– M37 (NGC 2099), the brightest open star cluster in Auriga, is around 24 light years across and 4,511 light-years distant. It has a visual magnitude of 5.6, and contains around 500 stars that are roughly 400 million years old.
– M38 (NGC 1912) is an open star cluster that is around 25 light years wide, and situated 4,200 light-years from our Sun . It has a magnitude of 7.9, and contains around 100 stars whose are estimated to be about 220 million years old.
Other objects of interest in Auriga includes two emission nebulae, namely the Flaming Star Nebula (IC 405) found 1,500 light-years away; and C 410 lying 2,200 light-years distant.
Two meteor showers are connected with Auriga, the first being the Alpha Aurigids, a minor and unreliable shower associated with the comet Kiess (C/1911 N1), that occurs between August 25th and September 10th, and peaks on the 31st when around 5 meteors per hour can be seen. However, intervals between showers can extend over many years, with showers observed in 1935, (the year of its discovery), and then only again in 1986, 1994, and 2007. The second more reliable shower meteor shower is the Delta Aurigids, which can be seen from September 22nd to October 23rd, with its maximum occurring around the 4th when up to six meteors per hour may be seen.