  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 42m 28.63240s [1] |
| Declination | +01° 28′ 28.6714″ [1] |
| Apparent magnitude (V) | 4.90 [2] |
| Characteristics | |
| Spectral type | K1III [3] |
| U−B color index | +1.06 [2] |
| B−V color index | +1.17 [2] |
| Astrometry | |
| Radial velocity (Rv) | +87.55 [4] km/s |
| Proper motion (μ) | RA: −54.741 [1] mas/yr Dec.: −14.732 [1] mas/yr |
| Parallax (π) | 10.9178±0.2225 mas [1] |
| Distance | 299 ± 6 ly (92 ± 2 pc) |
| Absolute magnitude (MV) | 0.13 [5] |
| Details | |
| Mass | 1.11 [5] M☉ |
| Radius | 19.3+0.4 −1.0 [1] R☉ |
| Luminosity | 132±3 [1] L☉ |
| Surface gravity (log g) | 2.24 [6] cgs |
| Temperature | 4,458+92 −51 [1] K |
| Metallicity [Fe/H] | −0.45 [6] dex |
| Rotational velocity (v sin i) | 1.1 [7] km/s |
| Age | 4.06 [8] Gyr |
| Other designations | |
| b Ori, 51 Ori, BD+01°1105, FK5 2427, GC 7136, HD 37984, HIP 26885, HR 1963, SAO 113056 [9] | |
| Database references | |
| SIMBAD | data |
51 Orionis is a single [10] star in the equatorial constellation of Orion. [9] It has the Bayer designation b Orionis, while 51 Orionis is the Flamsteed designation. This object is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.90. [2] It is located approximately 299 light-years away from the Sun based on parallax, [1] and is drifting further away with a radial velocity of +88 km/s. [4]
This is an aging giant star with a stellar classification of K1III, [3] having exhausted the supply of hydrogen at its core and expanded to 19 times the Sun's radius. [1] It is four [8] billion years old with 1.11 [5] times the mass of the Sun. The star is radiating 132 [1] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,458 K. [1]
