Eta Orionis
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| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Orion |
| Right ascension | 05h 24m 28.6167s |
| Declination | −02° 23′ 49.726″ |
| Apparent magnitude (V) | 3.38 |
| Characteristics | |
| Spectral type | B0.5V |
| U−B color index | 1.22 |
| B−V color index | −0.17 |
| Variable type | Beta Lyrae variable |
| Astrometry | |
| Radial velocity (Rv) | 19.8 km/s |
| Proper motion (μ) | RA: −0.54 mas/yr Dec.: −3.21 mas/yr |
| Parallax (π) | 3.62 ± 0.88 mas |
| Distance | approx. 900 ly (approx. 280 pc) |
| Absolute magnitude (MV) | −3.8 |
| Details | |
| Mass | 20 M☉ |
| Radius | 10 R☉ |
| Luminosity | 38,000 L☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
Eta Orionis (η Ori, η Orionis) is a star in the constellation Orion. Other names are Saiph,[1] Algjebbah,[2] and Ensis (Latin for "sword", since the star is taken to represent Orion's sheathed weapon).
It is a star system at a distance of 900 light years from Earth and part of the Orion Arm. Eta Orionis lies a little to the west of Orion's belt between Delta Orionis and Rigel, being closer to Delta Orionis than to Rigel. It is an eclipsing binary system consisting of two blue stars orbiting one another in a regular pattern.
[edit] See also
[edit] Notes
- ^ Allen, R. H. (1899). Star-Names and Their Meanings. New York: G. E. Stechert. p. 316.
Saiph was also used to indicate Kappa Orionis in the same constellation. - ^ Moore, P. (1983). The Guinness Book of Astronomy: Facts and Feats (2nd ed.). Middlesex: Guinness Superlatives Limited. p. 230.
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