Star in the constellation Auriga From Wikipedia, the free encyclopedia
12 Aurigae is a Be star in the northern constellation Auriga. It lies below the normal limit for visibility to the naked eye, having an apparent visual magnitude of 6.988.[2] It lacks a designation from the Hipparcos catalogue. It is located just under half a degree north of Capella.[8]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Auriga |
| Right ascension | 05h 16m 27.08298s[1] |
| Declination | +46° 24′ 57.8118″[1] |
| Apparent magnitude (V) | 6.988[2] |
| Characteristics | |
| Spectral type | B2 Ve[3] |
| Astrometry | |
| Proper motion (μ) | RA: −3.321[1] mas/yr Dec.: −1.2106[1] mas/yr |
| Parallax (π) | 1.5264 ± 0.0303 mas[1] |
| Distance | 2,140 ± 40 ly (660 ± 10 pc) |
| Details | |
| Mass | 3.0[4] M☉ |
| Radius | 18[5] R☉ |
| Luminosity | 635[5] L☉ |
| Surface gravity (log g) | 2.47[4] cgs |
| Temperature | 8,688[6] K |
| Metallicity | −0.94[4] |
| Rotational velocity (v sin i) | 100±41[7] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Assigned spectral classes for 12 Aurigae vary greatly from B2 to B5 and the luminosity class from V (main sequence) to Ia (luminous supergiant). Its spectrum shows prominent emission lines, but the spectrum is complicated by the appearance of sharp shell components to some of the spectral lines.[9] The colour of the star as shown by the B-V and U-B colour indices is not consistent with an early B spectral class,[10] leading to many estimates of its effective temperature that are much lower than expected for a B-class star.[6][4] The expected temperature for a B5 spectral type would be 15,400 K,[11] but most sources assign a temperature of around 8,000 K.[6][4] Other properties also vary between different sources, for example the bolometric luminosity derived from the distance and temperature is 25 L☉,[6] while it is 635 L☉ when derived by fitting the spectral energy distribution.[5] A calculation of the stellar properties assuming the maximum possible interstellar extinction in the direction of 12 Aurigae results in a temperature of 14,336 K and a luminosity of 8,092 L☉, although it is strongly noted that the likely extinction is much lower.[5]
Seamless Wikipedia browsing. On steroids.