Xi Cygni

ξ Cygni (Latinised as Xi Cygni) is a spectroscopic binary star in the constellation Cygnus. Its apparent magnitude is 3.73 and it is located around 360 parsecs (1,200 ly) away.

ξ Cygni
Location of ξ Cygni (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus
Right ascension 21h 04m 55.874s[1]
Declination +43° 55′ 40.285″[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: +9.763[5] mas/yr
Dec.: +0.646[5] mas/yr
Parallax (π)3.59 ± 0.45 mas[5]
Distanceapprox. 900 ly
(approx. 280 pc)
Absolute magnitude (MV)−4.3/+1.3[3]
Orbit[6]
Period (P)6,750 ± 200 days
Semi-major axis (a)~766 R☉
Eccentricity (e)0.25 ± 0.07
Inclination (i)~50°
Details
Primary
Mass~8[6] M☉
Radius174[1] R☉
Luminosity6,081 - 6,368[1] L☉
Surface gravity (log g)1.00[7] cgs
Temperature3,898±170[1] K
Metallicity [Fe/H]−0.41[7] dex
Secondary
Mass~2.5[6] M☉
Other designations
62 Cygni, FK5 792, GC 29459, HIP 104060, HR 8079, HD 200905, SAO 50424
Database references
SIMBADdata

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.[6]

ξ Cygni is in the Kepler spacecraft's field of view but no planets have been detected.[8]

  • H-alpha RGB amateur image of ξ Cygni, center star, at edge of NGC7000
    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.
    NGC 7000 (North America Nebula). ξ Cygni is the bright star on the left.

References
  1. Messineo, M.; Brown, A. G. A. (2019). "A Catalog of Known Galactic K-M Stars of Class I Candidate Red Supergiants in Gaia DR2". The Astronomical Journal. 158 (1): 20. arXiv:1905.03744. Bibcode:2019AJ....158...20M. doi:10.3847/1538-3881/ab1cbd. S2CID 148571616.
  2. Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237: 0. Bibcode:2002yCat.2237....0D.
  3. Ginestet, N.; Carquillat, J. M. (2002). "Spectral Classification of the Hot Components of a Large Sample of Stars with Composite Spectra, and Implication for the Absolute Magnitudes of the Cool Supergiant Components". The Astrophysical Journal Supplement Series. 143 (2): 513. Bibcode:2002ApJS..143..513G. doi:10.1086/342942.
  4. Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272, S2CID 17804304
  5. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  6. Reimers, D.; Schroeder, K.-P. (1989). "Observations of modulation and phase displacement of the stellar wind in six red giant spectroscopic binaries". Astronomy and Astrophysics. 214: 261. Bibcode:1989A&A...214..261R.
  7. Hekker, S.; Meléndez, J. (2007). "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters". Astronomy and Astrophysics. 475 (3): 1003. arXiv:0709.1145. Bibcode:2007A&A...475.1003H. doi:10.1051/0004-6361:20078233. S2CID 10436552.
  8. Molenda-Żakowicz, J.; Sousa, S. G.; Frasca, A.; Uytterhoeven, K.; Briquet, M.; Van Winckel, H.; Drobek, D.; Niemczura, E.; Lampens, P.; Lykke, J.; Bloemen, S.; Gameiro, J. F.; Jean, C.; Volpi, D.; Gorlova, N.; Mortier, A.; Tsantaki, M.; Raskin, G. (2013). "Atmospheric parameters of 169 F-, G-, K- and M-type stars in the Kepler field". Monthly Notices of the Royal Astronomical Society. 434 (2): 1422. arXiv:1306.6011. Bibcode:2013MNRAS.434.1422M. doi:10.1093/mnras/stt1095. S2CID 59269553.
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