Beta Aurigae
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| Observation data Epoch J2000.0 |
|
|---|---|
| Constellation (pronunciation) |
Auriga |
| Right ascension | 05h 59m 31.7s |
| Declination | +44° 56′ 51″ |
| Apparent magnitude (V) | +1.90 (2.56/2.8/10.6) |
| 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 (Rv) | −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 (MV) | −0.11 |
| Details | |
| Mass | ? M☉ |
| Radius | 3 R☉ |
| Luminosity | 95 L☉ |
| Temperature | 8,800 K |
| Metallicity | 100% Sun |
| Rotation | 37 km/s |
| Age | ? years |
| Other designations | |
| 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 a white star of spectral class A , similar to Vega, Denebola, and Sirius. Beta Aurigae is also a subgiant star, which means it has started to change from burning hydrogen to burning helium, has moved off the main sequence, and is slowly expanding into a giant star like Aldebaran.
Beta Aurigae is actually a ternary (triple) star system. The two brightest components, Beta Aurigae A and B, are both white subgiants. Star B is about the same mass and radius as A. Beta Aurigae A and B form an eclipsing spectroscopic binary; the combined 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 naked-eye visibility. 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
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