Xi Cygni

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ξ Cygni
Cygnus constellation map.svg
Red circle.svg

Location of ξ Cygni (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus
Right ascension 21h 04m 55.86s[1]
Declination +43° 55′ 40.3″[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: +7.97[1] mas/yr
Dec.: +0.06[1] mas/yr
Parallax (π) 3.87 ± 0.16[1] mas
Distance 361[3] pc
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
Primary
Mass ~8[5] M
Radius 200[5] R
Luminosity 5,303[6] L
Surface gravity (log g) 1.00[7] cgs
Temperature 3,920[7] K
Metallicity [Fe/H] −0.41[7] 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

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.

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 a 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]

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.
NGC 7000 (North America Nebula). ξ Cygni is the bright star on the left.

References[edit]

  1. ^ a b c d e van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752Freely accessible. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. 
  2. ^ a b c 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. ^ a b c 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/0409579Freely accessible, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272 
  5. ^ a b c d e 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. 
  6. ^ McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012). "Fundamental parameters and infrared excesses of Hipparcos stars". Monthly Notices of the Royal Astronomical Society. 427: 343. arXiv:1208.2037Freely accessible. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x. 
  7. ^ a b c Hekker, S.; Meléndez, J. (2007). "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters". Astronomy and Astrophysics. 475 (3): 1003. arXiv:0709.1145Freely accessible. Bibcode:2007A&A...475.1003H. doi:10.1051/0004-6361:20078233. 
  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:1306.6011Freely accessible. Bibcode:2013MNRAS.434.1422M. doi:10.1093/mnras/stt1095.