Omicron Aurigae

Omicron Aurigae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Auriga
Right ascension 05h 45m 54.042s
Declination +49° 49 34.58
Apparent magnitude (V) +5.47
Characteristics
Spectral type A1 Cr Eu
U−B color index +0.02
B−V color index +0.02
Astrometry
Radial velocity (Rv)−7.7±0.9 km/s
Proper motion (μ) RA: −11.087 mas/yr
Dec.: +3.703 mas/yr
Parallax (π)8.1876±0.2643 mas
Distance400 ± 10 ly
(122 ± 4 pc)
Absolute magnitude (MV)−0.03
Details
Mass1.9 M
Radius3.2 R
Luminosity50 L
Surface gravity (log g)3.7 cgs
Temperature8,300 K
Rotational velocity (v sin i)35.2±5.3 km/s
Other designations
ο Aur, 27 Aur, BD+49°1398, FK5 216, HD 38104, HIP 27196, HR 1971, SAO 40583
Database references
SIMBADdata

Omicron Aurigae is an astrometric binary 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, it is faintly visible to the naked eye. Based upon an annual parallax shift of 8.19 mas, 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. The star is a member of the Ursa Major stream of co-moving stars.

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). A magnetic field has been detected and it is a source of X-ray emission with a luminosity of: log Lx = 29.1. 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.