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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Aries |
| Right ascension | 02h 44m 32.97317s[1] |
| Declination | +15° 18′ 42.7085″[1] |
| Apparent magnitude (V) | +5.78[2] |
| Characteristics | |
| Spectral type | B9 Vn[3] |
| U−B color index | −0.21[4] |
| B−V color index | −0.01[4] |
| Astrometry | |
| Radial velocity (Rv) | −2.4±3.3[5] km/s |
| Proper motion (μ) | RA: +3.25[1] mas/yr Dec.: −14.87[1] mas/yr |
| Parallax (π) | 5.49 ± 0.32[1] mas |
| Distance | 590 ± 30 ly (180 ± 10 pc) |
| Absolute magnitude (MV) | −0.51[6] |
| Details | |
| Mass | 3.45±0.09[7] M☉ |
| Radius | 3.1[8] R☉ |
| Luminosity | 248[7] L☉ |
| Temperature | 10,715[7] K |
| Rotational velocity (v sin i) | 225[9] km/s |
| Age | 286[10] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Omicron Arietis, Latinised from ο Arietis, is the Bayer designation for a single,[2] blue-white-hued star in the northern constellation of Aries. It has an apparent visual magnitude of +5.78,[2] which means it is dimly visible to the naked eye. Based upon an annual parallax shift of 5.49 mas as seen from Earth,[1] it is located roughly 590 light-years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.22 due to interstellar dust.[10]
This is a B-type main-sequence star with a stellar classification of B9 Vn.[3] The 'n' suffix indicates that it has nebulous absorption lines in its spectrum, which are caused by the Doppler effect and rapid rotation. Indeed, it has a projected rotational velocity of 225 km/s.[9] The star has an estimated 3.45[7] times the mass of the Sun and about 3.1[8] times the Sun's radius. It is radiating energy from its photosphere at 248 times the Sun's luminosity with an effective temperature of 10,715 K.[7]