Phi Cygni

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Phi Cygni
Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus
Right ascension 19h 39m 22.60591s [1]
Declination 30° 09′ 11.9604″ [1]
Apparent magnitude (V) 4.69 [2]
Spectral type G8III-IV [3]
B−V color index +0.96 [2]
Radial velocity (Rv) +4.50[4] km/s
Proper motion (μ) RA: +2.48[2] mas/yr
Dec.: +36.50[2] mas/yr
Parallax (π) 12.25 ± 0.24[1] mas
Distance 266 ± 5 ly
(82 ± 2 pc)
Absolute magnitude (MV) 0.13 [5]
Radius 7.80 [6] R
Other designations
12 Cygni, FK5 3570, GC 27203, HIP 96683, HR 7478, HD 185734, SAO 68637, WDS J19394+3009AB [2]
Database references

Phi Cygni (φ Cyg) is a class G8III[3] (yellow giant) star in the constellation Cygnus. Its apparent magnitude is 4.69[2] and it is approximately 266 light years away based on parallax.[1] It is a spectroscopic binary with two similar stars orbiting with a period of 434 days.[7][8]


  1. ^ a b c d van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752free to read. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.  Vizier catalog entry
  2. ^ a b c d e f "Phi Cygni". SIMBAD Astronomical Database. Retrieved 2016-04-10. 
  3. ^ a b Jaschek, M. (July 1978), "Catalogue of selected spectral types in the MK system", Bulletin d'Information du Centre de Donnees Stellaires, 15 (121), Bibcode:1978BICDS..15..121J  Vizier catalog entry
  4. ^ Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; Levato, H.; Morrell, N. I.; Torres, G.; Udry, S. (September 2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy and Astrophysics, 424: 727–732, arXiv:astro-ph/0406573free to read, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213 
  5. ^ Absolute magnitude calculated as , where is the star's absolute magnitude, is the star's apparent magnitude, and is the star's measured parallax in arcseconds.
  6. ^ Pasinetti Fracassini, L. E.; Pastori, L.; Covino, S.; Pozzi, A. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition", Astronomy and Astrophysics, 367: 521–524, arXiv:astro-ph/0012289free to read, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451  Vizier catalog entry
  7. ^ Malkov, O. Yu.; et al. (October 2012), "Dynamical masses of a selected sample of orbital binaries", Astronomy & Astrophysics, 546 (A69), Bibcode:2012A&A...546A..69M, doi:10.1051/0004-6361/201219774  Vizier catalog entry
  8. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878free to read, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x  Vizier catalog entry