Xi Cygni
Star in the constellation Cygnus
From Wikipedia, the free encyclopedia
ξ Cygni (Latinised as Xi Cygni) is a spectroscopic binary star in the constellation Cygnus, made up of a K-type supergiant star (primary) and an A-type star (secondary). Its apparent magnitude is 3.73, making it readily visible to the naked eye, and it is located around 350 parsecs (1,100 ly) away.
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 21h 04m 55.8599s[1] |
| Declination | +43° 55′ 40.272″[1] |
| Apparent magnitude (V) | 3.73[2] |
| Characteristics | |
| Spectral type | K4:Ib- + A1.5V[3] |
| U−B color index | +1.78[2] |
| B−V color index | +1.66[2] |
| Astrometry | |
| Radial velocity (Rv) | −19.10[4] km/s |
| Proper motion (μ) | RA: +10.062[1] mas/yr Dec.: +0.861[1] mas/yr |
| Parallax (π) | 2.8363±0.1269 mas[1] |
| Distance | 1,150 ± 50 ly (350 ± 20 pc)[1] |
| Absolute magnitude (MV) | −4.3/+1.3[3] |
| Orbit[5] | |
| Period (P) | 6,750 ± 200 days |
| Semi-major axis (a) | ~766 R☉ |
| Eccentricity (e) | 0.25 ± 0.07 |
| Inclination (i) | ~50° |
| Details[6] | |
| Primary | |
| Mass | ~8[5] M☉ |
| Radius | 220.09+9.64 −10.56 R☉ |
| Luminosity | 9889±964 L☉ |
| Surface gravity (log g) | 0.89 cgs |
| Temperature | 3,878±33 – 4,031 K |
| Metallicity [Fe/H] | −0.26 dex |
| Secondary | |
| Mass | ~2.5[5] M☉ |
| Other designations | |
| 62 Cygni, FK5 792, GC 29459, HIP 104060, HR 8079, HD 200905, SAO 50424 | |
| Database references | |
| SIMBAD | data |
Characteristics
The system contains two stars which orbit every 18 years in a mildly eccentric orbit. The primary star is a supergiant with a spectral type of around K4, while the secondary is an A-type main-sequence star with a spectral type of A1.5. Stellar winds from the supergiant have been measured at around 50 km/s, but with variations in speed and individual line strengths.[5]
The distance to Xi Cygni is of about 350 parsecs (1,100 ly), based on parallax measurements.[1] At this distance, the apparent magnitude is diminished by 0.16 magnitudes.[6]
ξ Cygni is in the Kepler spacecraft's field of view but no planets have been detected.[7]
Gallery
H-alpha RGB amateur image of ξ Cygni, center star, at edge of NGC7000
NGC 7000 (North America Nebula). ξ Cygni is the bright star on the left.
