51 Orionis
Star in the constellation of Orion
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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]
 | |
| 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 |
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]