Zeta-2 Scorpii
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) |
|
|---|---|
| Constellation | Scorpius |
| Right ascension | 16h 54m 35.00435s |
| Declination | −42° 21′ 40.7407″ |
| Apparent magnitude (V) | 3.59 to 3.65 |
| Characteristics | |
| Spectral type | K4 III |
| U−B color index | +1.65 |
| B−V color index | +1.37 |
| R−I color index | +0.68 |
| Astrometry | |
| Radial velocity (Rv) | −18.7±0.9 km/s |
| Proper motion (μ) |
RA: −127.72 mas/yr Dec.: −229.44 mas/yr |
| Parallax (π) | 24.65 ± 0.27mas |
| Distance | 132 ± 1 ly (40.6 ± 0.4 pc) |
| Absolute magnitude (MV) | 0.30±0.09 |
| Details | |
| Mass | 1.19±0.14 M☉ |
| Radius | 21.0±1.6 R☉ |
| Surface gravity (log g) | 1.84±0.10 cgs |
| Temperature | 4,169 K |
| Metallicity [Fe/H] | +0.06 dex |
| Rotational velocity (v sin i) | 2.30 km/s |
| Age | 5.80±2.26 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Zeta2 Scorpii (Zeta2 Sco, ζ2 Scorpii, ζ2 Sco) is a K-type orange giant star in the constellation of Scorpius. It has an apparent visual magnitude which varies between 3.59 and 3.65, and is located near the blue-white supergiant star ζ1 Scorpii in Earth's sky. In astronomical terms, ζ2 is much closer to the Sun and unrelated to ζ1 except for line-of sight co-incidence. ζ1 is 5,700 light-years away and probably an outlying member of open star cluster NGC 6231 (also known as the "northern jewel box" cluster), whereas ζ2 is a mere 132 lightyears distant and thus much less luminous in real terms. ζ2 can also be distinguished from its optical partner, ζ1, because of its orangish colour especially in long-exposure astrophographs.
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