66 Aurigae
Star in the constellation Auriga
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66 Aurigae (also named fyozai) is a single[7] star located approximately 880 light years away from the Sun in the northern constellation of Auriga. It is visible to the naked eye as a faint, orange hued star with an apparent magnitude of 5.23.[1] This object is moving further from the Earth with a heliocentric radial velocity of +22.6 km/s.[2]
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Auriga[1] |
| Right ascension | 07h 24m 08.46679s[2] |
| Declination | +40° 40′ 20.5980″[2] |
| Apparent magnitude (V) | 5.23[1] |
| Characteristics | |
| Evolutionary stage | horizontal branch[3] |
| Spectral type | K0.5 IIIa[4] |
| B−V color index | 1.249±0.003[1] |
| Astrometry | |
| Radial velocity (Rv) | +22.62±0.13[2] km/s |
| Proper motion (μ) | RA: −3.511[2] mas/yr Dec.: −20.935[2] mas/yr |
| Parallax (π) | 3.7070±0.1684 mas[2] |
| Distance | 880 ± 40 ly (270 ± 10 pc) |
| Absolute magnitude (MV) | −2.58[1] |
| Details | |
| Mass | 5.05[3] M☉ |
| Radius | 48.05+1.66 −1.36[2] R☉ |
| Luminosity | 834.3±43.6[2] L☉ |
| Temperature | 4,475+65 −75[2] K |
| Metallicity [Fe/H] | 0.09±0.03[1] dex |
| Rotational velocity (v sin i) | 4.5[5] km/s |
| Age | 107[3] Myr |
| Other designations | |
| 66 Aur, BD+40°1852, FK5 1191, GC 9850, HD 57669, HIP 35907, HR 2805, SAO 41738[6] | |
| Database references | |
| SIMBAD | data |
At the age of 107 million years,[3] 66 Aurigae is an evolved giant star, most likely (98% chance) on the horizontal branch,[3] with a stellar classification of K0.5 IIIa.[4] Keenan and Yorka (1987) identified it as a strong–CN star, showing an excess strength of the blue CN bands in the spectrum.[8] Having exhausted the supply of hydrogen at its core, the star has expanded to 48[2] times the Sun's radius. 66 Aurigae has five[3] times the mass of the Sun and is radiating 834[2] times the Sun's luminosity from its swollen photosphere at an effective temperature of 4,475 K.[2]
It was also known to be part of a much bigger constellation named Telescopium Herschelii before it was unrecognized by the International Astronomical Union (IAU).