Zeta Ophiuchi
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| Observation data Epoch J2000 |
|
|---|---|
| Constellation (pronunciation) |
Ophiuchus |
| Right ascension | 16h 37m 09.5s |
| Declination | -10° 34′ 01.4″ |
| Apparent magnitude (V) | 2.54 |
| Characteristics | |
| Spectral type | O9 III |
| U-B color index | -0.86 |
| B-V color index | 0.02 |
| Variable type | Gamma Cass. |
| Astrometry | |
| Radial velocity (Rv) | -15 km/s |
| Proper motion (μ) | RA: 13.07 mas/yr Dec.: 25.44 mas/yr |
| Parallax (π) | 7.12 ± 0.71 mas |
| Distance | 458 ly (140 pc) |
| Absolute magnitude (MV) | -3.20 |
| Details | |
| Mass | 20 M☉ |
| Radius | 8 R☉ |
| Luminosity | 68,000 L☉ |
| Temperature | 33,500 K |
| Metallicity | titanium |
| Rotation | 380 km/s. |
| Age | 4 × 106 years |
| Other designations | |
Zeta Ophiuchi (ζ Oph / ζ Ophiuchi) is a star located in the constellation of Ophiuchus. Unlike most of the brighter stars in the sky, ζ Ophiuchi does not have a proper name, although it may have been referred to as Hán (韓) by the Chinese. Although ζ Ophiuchi is a hot blue giant star it appears reddish due to interstellar dust that absorbs much of blue light. In fact, were it not for this dust, ζ Ophiuchi would shine several times brighter and be among the very brightest visible. ζ Ophiuchi is roughly half way through the initial phase of its stellar evolution and will within the next few million years expand into a supergiant star before ending its life in a spectacular supernova.
[edit] References
- HD 149757 -- Be Star. SIMBAD Astronomical Database. Retrieved on 2007-03-29.
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