Auriga (constellation) - Notable Features - Stars - Bright Stars

Bright Stars

Alpha Aurigae (Capella), the brightest star in Auriga, is a G8III class star (G-type giant) 43 light-years away and the sixth brightest star in the night sky at magnitude 0.08. Its traditional name is a reference to its mythological position as Amalthea; it is sometimes called the "Goat Star". Capella's names all point to this mythology. In Arabic, Capella was called al-'Ayyuq, meaning "the goat", and in Sumerian, it was called mul.ÁŠ.KAR, "the goat star". On Ontong Java, Capella was called ngahalapolu. Capella is a spectroscopic binary with a period of 104 days; the components are both yellow giants, more specifically, the primary is a G-type star and the secondary is between a G-type and F-type star in its evolution. The secondary is formally classified as a G0III class star (G-type giant). The primary has a radius of 11.87 solar radii (R_☉) and a mass of 2.47 solar masses (M_☉); the secondary has a radius of 8.75 R_☉ and a mass of 2.44 M_☉. The two components are separated by 110 million kilometers, almost 75% of the distance between the Earth and the Sun. The star's status as a binary was discovered in 1899 at the Lick Observatory; its period was determined in 1919 by J.A. Anderson at the 100-inch Mt. Wilson Observatory telescope. It appears with a golden-yellow hue, though Ptolemy and Giovanni Battista Riccioli both described its color as red, a phenomenon attributed not to a change in Capella's color but to the idiosyncrasies of their color sensitivities. Capella has an absolute magnitude of 0.3 and a luminosity of 160 times the luminosity of the Sun, or 160 L_☉ (the primary is 90 L_☉ and the secondary is 70 L_☉). It may be loosely associated with the Hyades, an open cluster in Taurus, because of their similar proper motion. Capella has one more companion, Capella H, which is a pair of red dwarf stars located 11,000 astronomical units (0.17 light-years) from the main pair.

Beta Aurigae (Menkalinan, Menkarlina) is a bright A2IV class star (A-type subgiant). Its Arabic name comes from the phrase mankib dhu al-'inan, meaning "shoulder of the charioteer" and is a reference to Beta Aurigae's location in the constellation. Menkalinan is 81 light-years away and has a magnitude of 1.90. Like Epsilon Aurigae, it is an eclipsing binary star that varies in magnitude by 0.1m. The two components are blue-white stars that have a period of 3.96 days. Its double nature was revealed spectroscopically in 1890 by Antonia Maury, making it the second spectroscopic binary discovered, and its variable nature was discovered photometrically 20 years later by Joel Stebbins. Menkalinan has an absolute magnitude of 0.6 and a luminosity of 50 L_☉. The component of its motion in the direction of Earth is 18 kilometres (11 mi) per second. Beta Aurigae may be associated with a stream of abount 70 stars including Delta Leonis and Alpha Ophiuchi; the proper motion of this group is comparable to that of the Ursa Major Moving Group, though the connection is only hypothesized. Besides its close eclipsing companion, Menkalinan has two other stars associated with it. One is an unrelated optical companion, discovered in 1783 by William Herschel; it has a magnitude of 10.5 and has a separation of 184 arcseconds. The other is likely associated gravitationally with the primary, as determined by their common proper motion. This 14th magnitude star was discovered in 1901 by Edward Emerson Barnard. It has a separation of 12.6 arcseconds, and is around 350 astronomical units from the primary.