Beta Ophiuchi
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| Observation data Epoch J2000.0 (ICRS) |
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|---|---|
| Constellation (pronunciation) |
Ophiuchus |
| Right ascension | 17h 43m 28.353s |
| Declination | +04° 34′ 02.29″ |
| Apparent magnitude (V) | 2.75 to 2.77 |
| Characteristics | |
| Spectral type | K2III |
| U-B color index | 1.24 |
| B-V color index | 1.16 |
| Variable type | K-type giant[1],[2] |
| Astrometry | |
| Radial velocity (Rv) | -12 km/s |
| Proper motion (μ) | RA: -40.67 mas/yr Dec.: 158.80 mas/yr |
| Parallax (π) | 39.78 ± 0.75 mas |
| Distance | 82 ± 2 ly (25.1 ± 0.5 pc) |
| Absolute magnitude (MV) | 0.75 to 0.77 |
| Other designations | |
| Data sources: | |
| Hipparcos Catalogue, Bright Star Catalogue (5th rev. ed.), GCVS (4.2),[1],[2] |
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Beta Ophiuchi (β Oph / β Ophiuchi) is a K-type giant star in the constellation Ophiuchus. It also has the traditional names Cebalrai (Arabic: "shepherd dog"), Cheleb, or Kelb Alrai, or sometimes just Alrai. Like some other K-type giants, β Ophiuchi has been found to vary very slightly (0.02 magnitudes) in brightness.[1],[2]
[edit] References
- ^ a b c K Giants in 47 Tucanae: Detection of a New Class of Variable Stars, Peter D. Edmonds and Roland L. Gilliland, Astrophysical Journal Letters 464 (June 1996), pp. L157–L160
- ^ a b c The Radial Velocity Variability of the K Giant beta Ophiuchi. II. Long-Period Variations, Artie P. Hatzes and William D. Cochran, Astrophysical Journal 468 (September 1996), pp. 391–397
