Alnilam
Alnilam is the central star of Orion's Belt in the equatorial constellation of Orion. It has the Bayer designation ε Orionis, which is Latinised to Epsilon Orionis and abbreviated Epsilon Ori or ε Ori. This is a massive, blue supergiant star some 2,000 light-years distant. It is estimated to be 832,000 times as luminous as the Sun, and 64.5 times as massive.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion |
| Pronunciation | /ælˈnaɪlæm/ |
| Right ascension | 05h 36m 12.8s |
| Declination | −01° 12′ 06.9″ |
| Apparent magnitude (V) | 1.69 (1.64 – 1.74) |
| Characteristics | |
| Spectral type | B0 Ia |
| U−B color index | −1.03 |
| B−V color index | −0.18 |
| Variable type | α Cygni |
| Astrometry | |
| Radial velocity (Rv) | 25.9 km/s |
| Proper motion (μ) | RA: 1.49 mas/yr Dec.: −1.06 mas/yr |
| Parallax (π) | 1.65 ± 0.45 mas |
| Distance | approx. 2,000 ly (approx. 600 pc) |
| Absolute magnitude (MV) | −6.89 |
| Details | |
| Mass | 64.5 M☉ |
| Radius | 42.0 R☉ |
| Luminosity | 832,000 L☉ |
| Surface gravity (log g) | 3.0 cgs |
| Temperature | 27,000±500 K |
| Rotational velocity (v sin i) | 40–70 km/s |
| Age | 5.7 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.