Zeta2 Scorpii
Star in the constellation Scorpius. / From Wikipedia, the free encyclopedia
For other stars with this Bayer designation, see Zeta Scorpii.
Zeta2 Scorpii (Zeta2 Sco, ζ2 Scorpii, ζ2 Sco) is a K-type orange giant star in the constellation of Scorpius.[8] It has an apparent visual magnitude which varies between 3.59 and 3.65,[2] 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 about 6,000 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 135 light-years 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 astrophotographs.
Quick Facts Constellation, Right ascension ...
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Scorpius |
Right ascension | 16h 54m 35.00503s[1] |
Declination | −42° 21′ 40.7370″[1] |
Apparent magnitude (V) | 3.59 to 3.65[2] |
Characteristics | |
Spectral type | K4 III[3] |
U−B color index | +1.65[4] |
B−V color index | +1.37[4] |
R−I color index | +0.68[4] |
Astrometry | |
Radial velocity (Rv) | −18.7±0.9[5] km/s |
Proper motion (μ) | RA: −126.721 mas/yr[1] Dec.: −228.837 mas/yr[1] |
Parallax (π) | 24.2353 ± 0.1985 mas[1] |
Distance | 135 ± 1 ly (41.3 ± 0.3 pc) |
Absolute magnitude (MV) | 0.30±0.09[6] |
Details | |
Mass | 1.19±0.14[6] M☉ |
Radius | 21.0±1.6[6] R☉ |
Surface gravity (log g) | 1.84±0.10[6] cgs |
Temperature | 4,169[6] K |
Metallicity [Fe/H] | +0.06[6] dex |
Rotational velocity (v sin i) | 2.30[7] km/s |
Age | 5.80±2.26[6] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
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