Omicron Aurigae
Star in the constellation Auriga
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Omicron Aurigae is an astrometric binary[10] star system in the northern constellation of Auriga. Its name is a Bayer designation that is Latinized from ο Aurigae, and abbreviated Omicron Aur or ο Aur. With an apparent visual magnitude of 5.47,[3] it is faintly visible to the naked eye. Based upon an annual parallax shift of 8.19 mas,[2] it is approximately 400 light-years (120 parsecs) distant from Earth. It is drifting closer to the Sun with a radial velocity of −8 km/s.[6] The star is a member of the Ursa Major stream of co-moving stars.[11]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Auriga[1] |
| Right ascension | 05h 45m 54.042s[2] |
| Declination | +49° 49′ 34.58″[2] |
| Apparent magnitude (V) | +5.47[3] |
| Characteristics | |
| Spectral type | A1 Cr Eu[4] |
| U−B color index | +0.02 |
| B−V color index | +0.02[5] |
| Astrometry | |
| Radial velocity (Rv) | −7.7±0.9[6] km/s |
| Proper motion (μ) | RA: −11.087 mas/yr[2] Dec.: +3.703 mas/yr[2] |
| Parallax (π) | 8.1876±0.2643 mas[2] |
| Distance | 400 ± 10 ly (122 ± 4 pc) |
| Absolute magnitude (MV) | −0.03[1] |
| Details | |
| Mass | 1.9[7] M☉ |
| Radius | 3.2[7] R☉ |
| Luminosity | 50[7] L☉ |
| Surface gravity (log g) | 3.7[7] cgs |
| Temperature | 8,300[7] K |
| Rotational velocity (v sin i) | 35.2±5.3[7] km/s |
| Age | 657[8] Myr |
| Other designations | |
| ο Aur, 27 Aur, BD+49°1398, FK5 216, HD 38104, HIP 27196, HR 1971, SAO 40583[9] | |
| Database references | |
| SIMBAD | data |
The visible component is a chemically peculiar star with a stellar classification of A1 Cr Eu; meaning this is an A-type star with a spectrum that shows anomalously high abundances of chromium (Cr) and europium (Eu).[4] A magnetic field has been detected and it is a source of X-ray emission with a luminosity of: log Lx = 29.1.[11] The star has 1.9 times the mass of the Sun and 3.2 times the Sun's radius. It is spinning with a projected rotational velocity of 35 km/s and is radiating 50 times the Sun's luminosity from its photosphere at an effective temperature of 8,300 K.[7]