42 Orionis
Star in the constellation of Orion
From Wikipedia, the free encyclopedia
42 Orionis, also known as c Orionis or c Ori, is a class B1V[3] (blue main-sequence) star in the constellation Orion. Its apparent magnitude is 4.59[2] and it is approximately 900 light years away based on parallax.[1]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 35m 23.16427s[1] |
| Declination | −04° 50′ 18.0881″[1] |
| Apparent magnitude (V) | 4.59[2] |
| Characteristics | |
| Spectral type | B1V[3] |
| U−B color index | −0.94[2] |
| B−V color index | −0.19[2] |
| Astrometry | |
| Radial velocity (Rv) | +28.40[4] km/s |
| Proper motion (μ) | RA: +4.52[1] mas/yr Dec.: −7.11[1] mas/yr |
| Parallax (π) | 3.69±1.20 mas[1] |
| Distance | approx. 900 ly (approx. 270 pc) |
| Details | |
| Mass | 12.0[5] M☉ |
| Radius | 7.0[6] R☉ |
| Luminosity | 10,737[7] L☉ |
| Surface gravity (log g) | 3.82[6] cgs |
| Temperature | 25,400[7] K |
| Rotational velocity (v sin i) | 20[8] km/s |
| Age | 2.6[5] Myr |
| 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 |
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.[9][10]
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.