Omega2 Cygni

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]

Omega² Cygni

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]

See also

• Omega¹ Cygni