Observation data Epoch J2000.0 Equinox J2000.0 |
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Constellation | Cygnus |
Right ascension | 21h 12m 56.1862s / 21h 12m 53.9ss |
Declination | +30° 13′ 36.897″ / +30° 12′ 36″ |
Apparent magnitude (V) | 3.20 / 11.6 |
Characteristics | |
Spectral type | G8III / ? |
U−B color index | +0.76 / ? |
B−V color index | +0.99 / ? |
Astrometry | |
Radial velocity (Rv) | 17.4 / ? km/s |
Proper motion (μ) | RA: 6.87 / ? mas/yr Dec.: -68.12 / ? mas/yr |
Parallax (π) | 21.62 ± 0.63 mas |
Distance | 151 ± 4 ly (46 ± 1 pc) |
Details | |
Mass | 3 / 2.5 M☉ |
Radius | ? R☉ |
Surface gravity (log g) | ? |
Luminosity | ? L☉ |
Temperature | 7125 K |
Metallicity | ? |
Rotation | ? |
Age | 400 million years |
Other designations | |
Database references | |
SIMBAD | data |
Zeta Cygni (ζ Cyg) and CCDM J21129+3014B form a binary star system in the constellation Cygnus, approximately 151 light-years away from Earth.
The main star, 3rd magnitude Zeta Cygni, is a yellow star of the spectral type G8III. It has a radius 14.7 times that of our Sun and shines 119 times brighter in comparison. Its most likely status is as a core-helium fusing giant star, although it could be in transition to gianthood with a tranquil helium core. Assuming the former, it has a mass 3.0 solar masses and an age of 400 million years. Zeta Cygni has an abundance of barium, and other heavy chemical elements, in its atmosphere.[1][3]
Zeta Cygni has a 12th magnitude companion, assumed to be a white dwarf. It orbits every 6489 days, or every 17.8 years. A theoretical study shows the system started off with solar masses of 3.0 and 2.5, but the more massive star lost some of its mass in becoming a white dwarf. It sent half a solar mass to Zeta Cygni, along with the heavy chemical elements it possesses today.[3]
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