![]() Alnilam lights up NGC 1990. Photograph by Glen Youman |
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Observation data Epoch J2000 Equinox J2000 |
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Constellation | Orion |
Right ascension | 05h 36m 12.8s |
Declination | −01° 12′ 06.9″ |
Apparent magnitude (V) | 1.70 |
Characteristics | |
Spectral type | B0 Ia |
U−B color index | −1.03 |
B−V color index | −0.19 |
Variable type | Alp Cyg |
Astrometry | |
Radial velocity (Rv) | 25.9 km/s |
Proper motion (μ) | RA: 1.49 mas/yr Dec.: −1.06 mas/yr |
Parallax (π) | 2.43 ± 0.91 mas |
Distance | approx. 1,300 ly (approx. 400 pc) |
Absolute magnitude (MV) | −6.4 |
Details | |
Radius | 24R☉ |
Luminosity | 275,000L☉ |
Surface gravity (log g) | 2.9 |
Temperature | 27,000K |
Rotational velocity (v sin i) | 91 km/s |
Other designations | |
Alnilam, ε Ori, 46 Orionis, 112 G. Orionis, HR 1903, BD -01°969, HD 37128, SAO 132346, FK5 210, HIP 26311, TD1 4963, 参宿二.
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Database references | |
SIMBAD | data |