15 Orionis
Star system in the constellation Orion
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15 Orionis is a suspected astrometric binary[11] star system in the equatorial constellation of Orion, near the border with Taurus. It is visible to the naked eye as a faint, yellow-white hued star with an apparent visual magnitude of 4.82.[2] The system is approximately 340 light years away from the Sun based on parallax. It is moving further from the Earth with a heliocentric radial velocity of +29 km/s,[5] having come to within 69 light-years some three million years ago.[6]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 09m 41.96481s[1] |
| Declination | +15° 35′ 49.9051″[1] |
| Apparent magnitude (V) | 4.82[2] |
| Characteristics | |
| Evolutionary stage | giant[3] |
| Spectral type | F2IV[4] |
| U−B color index | +0.19[2] |
| B−V color index | +0.32[2] |
| Astrometry | |
| Radial velocity (Rv) | +28.79[5] km/s |
| Proper motion (μ) | RA: −3.105[1] mas/yr Dec.: −3.444[1] mas/yr |
| Parallax (π) | 9.5097±0.2951 mas[1] |
| Distance | 340 ± 10 ly (105 ± 3 pc) |
| Absolute magnitude (MV) | −0.04[6] |
| Details | |
| 15 Ori A | |
| Mass | 3.42±0.67[7] M☉ |
| Radius | 5.9[8] R☉ |
| Luminosity | 300[7] L☉ |
| Surface gravity (log g) | 3.75[9] cgs |
| Temperature | 7,161+50 −49[7] K |
| Metallicity [Fe/H] | +0.21[9] dex |
| Rotational velocity (v sin i) | 60[7] km/s |
| Age | 500[10] Myr |
| Other designations | |
| 15 Ori, BD+15°752, GC 6306, HD 33276, HIP 24010, HR 1676, SAO 94359, CCDM J05097+1536AB, WDS J05097+1536AB | |
| Database references | |
| SIMBAD | data |
The primary component is an early F-type subgiant star with a stellar classification of F2 IV,[4] a star that has exhausted the hydrogen at its core and has begun to evolve into a giant. It has 3.42 times the mass of the Sun[7] and 5.9 times the Sun's radius.[8] The star still has a relatively high rotation rate, showing a projected rotational velocity of 60 km/s.[7] It is radiating 300 times the luminosity of the Sun from its expanding photosphere at an effective temperature of 7,161 K.[7]
It has one suspected companion, component B, at a separation of 0.3".[12]