42 Orionis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 35m 23.16427s |
| Declination | −04° 50′ 18.0881″ |
| Apparent magnitude (V) | 4.59 |
| Characteristics | |
| Spectral type | B1V |
| U−B color index | −0.94 |
| B−V color index | −0.19 |
| Astrometry | |
| Radial velocity (Rv) | +28.40 km/s |
| Proper motion (μ) | RA: +4.52 mas/yr Dec.: −7.11 mas/yr |
| Parallax (π) | 3.69±1.20 mas |
| Distance | approx. 900 ly (approx. 270 pc) |
| Details | |
| Mass | 12.0 M☉ |
| Radius | 15.6 R☉ |
| Luminosity | 10.737 L☉ |
| Temperature | 25,400 K |
| Rotational velocity (v sin i) | 20 km/s |
| Other designations | |
| c Orionis, BD−04°1185, CCDM J05354-0450AB, GC 6934, HIP 26237, HR 1892, HD 37018, NSV 2318, SAO 132320, WDS J05354-0450AB | |
| Database references | |
| SIMBAD | data |
42 Orionis, also known as c Orionis or c Ori, is a class B1V (blue main-sequence) star in the constellation Orion. Its apparent magnitude is 4.59 and it is approximately 900 light years away based on parallax.
The primary star, Aa, has one spectroscopic companion Ab of magnitude 6.3 and separation 0.16", and a more distant companion B of 7.5 magnitude at 1.6" separation.
42 Orionis is surrounded by NGC 1977 one of a smaller fainter group of named nebulae just north of the Orion Nebula. 42 Ori is the star which excites and illuminates NGC 1977.