Omega2 Cygni
Star in the constellation Cygnus
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Omega2 Cygni, Latinized from ω2 Cygni, is the Bayer designation for a solitary[8] star in the northern constellation of Cygnus. It has an apparent visual magnitude of 5.5,[3] which is faintly visible to the naked eye on a dark night. Based upon an annual parallax shift of 7.18 mas,[2] it is located roughly 454 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.08 due to interstellar dust.[3]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cygnus[1] |
| Right ascension | 20h 31m 18.81655s[2] |
| Declination | +49° 13′ 13.0638″[2] |
| Apparent magnitude (V) | 5.5292±0.0013[3] |
| Characteristics | |
| Evolutionary stage | AGB[4] |
| Spectral type | M2 III[4] |
| Astrometry | |
| Radial velocity (Rv) | −64.15±0.20[3] km/s |
| Proper motion (μ) | RA: +8.959[2] mas/yr Dec.: −32.092[2] mas/yr |
| Parallax (π) | 7.1833±0.0675 mas[2] |
| Distance | 454 ± 4 ly (139 ± 1 pc) |
| Absolute magnitude (MV) | +0.00[1] |
| Details | |
| Mass | 1.4[5] M☉ |
| Radius | 45[6] R☉ |
| Luminosity | 398[6] L☉ |
| Surface gravity (log g) | 2.02[5] cgs |
| Temperature | 3,920[5] K |
| Metallicity [Fe/H] | −0.10[5] dex |
| Other designations | |
| ω2 Cyg, 46 Cygni, BD+48°3154, HD 195774, HIP 101243, HR 7851, SAO 49741.[7] | |
| Database references | |
| SIMBAD | data |
This is a red giant star on the asymptotic giant branch, with a stellar classification of M2 III.[4] It is a suspected variable star, although the evidence is considered "doubtful or erroneous". If it does exist, the variability is small with an amplitude of 0.05 magnitude and a timescale of around 30 days.[9] There is a 58.3% chance that this star is a member of the Hercules stream.[3]