Beta Aurigae

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**Beta Aurigae A / B / C**
Observation data Epoch J2000.0
Constellation	Auriga
Right ascension	05^h 59^m 31.7^s
Declination	+44° 56′ 51″
Apparent magnitude (V)	+1.90 (2.56/2.8/10.6)
Spectral Characteristics
Spectral type	A2IV / A2IV / MV
U-B color index	+0.05
B-V color index	+0.03
Variable type	Algol variable
Astrometry
Radial velocity (R_v)	−18.2 km/s
Proper motion (μ)	RA: −56.41 mas/yr Dec.: −0.88 mas/yr
Parallax (π)	39.72 ± 0.78 mas
Distance	82.1 ly (25.2 pc)
Absolute magnitude (M_V)	−0.11
Physical Characteristics
Mass	? M_☉
Radius	3 R_☉
Luminosity	95 L_☉
Temperature	8,800 K
Metallicity	100% Sun
Rotation	37 km/s
Age	? years
Other designations
Menkalinan, Menkarlina, 34 Aurigae, HR 2088, BD +44°1328, HD 40183, SAO 40750, NN 3375, GC 7543, FK5 227, ADS 4556, CCDM 05596+4457, HIP 28360
Database references
SIMBAD	data

Beta Aurigae (β Aur / β Aurigae), traditionally named Menkalinan (also written as Menkarlina), is a white subgiant star approximately 85 light-years away in the constellation Auriga.

The name Menkalinan is shortened from the Arabic منكب ذي العنان mankib ðī-l-‘inān "shoulder of the rein-holder".

Beta Aurigae is an A-star not much different from Vega, Denebola, and Sirius. Its color would be white with a blue tinge. Beta Aurigae is also a subgiant star which means it's starting to move from burning hydrogen to burning helium and slowly turning into a giant star like Aldebaran.

Beta Aurigae is actually a trinary star system. Beta Aurigae A is the white subgiant, yet so is Beta Aurigae B. It is about the same mass and radius as A. Beta Aurigae AB is an eclipsing spectroscopic binary, and its apparent magnitude varies over a period of 3.96004 days between +1.85 and +1.93, as every 47.5 hours one of the stars partially eclipses the other from Earth's perspective. The third star, Beta Aurigae C, is a red dwarf star that is far below the naked-eye vision. It is about 330 AU from the AB pair.

Beta Aurigae is believed to be a stream star member of the Ursa Major Moving Group. It is known as 五車三 ( the Third Star of the Five Chariots) in Chinese