| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Auriga |
| Right ascension | 05h 59m 31.72293s |
| Declination | +44° 56′ 50.7573″ |
| Apparent magnitude (V) | 1.90 |
| Astrometry | |
| Distance | 81 ly |
| Details | |
| A | |
| Mass | 2.38 M☉ |
| Radius | 2.76 R☉ |
| Luminosity | 47 L☉ |
| Temperature | 8,985 K |
| B | |
| Mass | 2.29 M☉ |
| Radius | 2.57 R☉ |
| Luminosity | 40 L☉ |
| Temperature | 8,760 K |
Beta Aurigae, abbreviated as β Aur and also named Menkalinan, is a star system in the northern constellation of Auriga. To the naked eye, it looks like a single bright star. However, it is actually a star system that have two binary stars orbiting each other every 3.96 days.
Both stars are subgiant stars, meaning they are brighter and larger than the Sun. They have begun to use up the hydrogen in their cores. Because these stars orbit so close together, they can form an eclipsing binary, periodically passing in front of one another, causing the system's brightness to decrease slightly as seen from Earth.
The two main stars are very similar in size and mass. The larger component has about 2.38 times the solar mass, with a solar radius of 2.76, and a surface temperature of approximately 8,985 K. The smaller component has a mass of about 2.29 solar masses, a radius of 2.57 solar radii, and a temperature of around 8,760 K. Astronomers estimate that this system is approximately 450 to 500 million years old.
