Eta Orionis
 Location of ε Orionis (circled) |
|
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Orion |
| Right ascension | 05h 24m 28.61672s[1] |
| Declination | –02° 23′ 49.7311″[1] |
| Apparent magnitude (V) | 3.42[2] |
| Characteristics | |
| Spectral type | B1 V + B3 V + B2 V[3] |
| U−B color index | –0.90[2] |
| B−V color index | −0.17[2] |
| Variable type | Algol[4] |
| Astrometry | |
| Radial velocity (Rv) | +19.8[5] km/s |
| Proper motion (μ) | RA: −0.71[1] mas/yr Dec.: −3.46[1] mas/yr |
| Parallax (π) | 3.34 ± 1.07[1] mas |
| Distance | approx. 1,000 ly (approx. 300 pc) |
| Details | |
| η Ori A | |
| Mass | 20 M☉ |
| Radius | 10 R☉ |
| Luminosity | 38,000 L☉ |
| Rotational velocity (v sin i) | 60[6] km/s |
| η Ori B | |
| Rotational velocity (v sin i) | 45[6] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Eta Orionis (η Ori, η Orionis) is a star in the constellation Orion. Other names are Saiph[8] (Arabic for "sword"), Algjebbah[9] (Arabic for "scutum"), and Ensis (Latin for "sword", since the star is taken to represent Orion's sheathed weapon). 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 lies at a distance of around 1,000 light years from Earth and is part of the Orion Arm.
This is a quadruple star system, of which three members can be resolved with a telescope. The primary component is an eclipsing binary star in a triple-star grouping. These stars have orbital periods of 8 days and 9.2 years. It includes a variable star with a pulsation period of around 8 hours. Three of the components are B-type main sequence stars with stellar classifications of B1 V, B3 V and B2 V.[3]
See also
References
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- ↑ 2.0 2.1 2.2 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ AAVSO International Variable Star Index VSX (Watson+, 2006-2012) VizieR
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Saiph was also used to indicate Kappa Orionis in the same constellation. - ↑ Lua error in package.lua at line 80: module 'strict' not found.
