17 Cygni

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17 Cygni
Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus
Right ascension 19h 46m 25.60019s[1]
Declination +33° 43′ 39.3452″[1]
Apparent magnitude (V) 5.00[2]
Spectral type F7 V[2] + M0.4[3]
B−V color index 0.46[2]
Radial velocity (Rv)+4.1[4] km/s
Proper motion (μ) RA: +23.25[1] mas/yr
Dec.: –449.31[1] mas/yr
Parallax (π)47.10 ± 0.26[1] mas
Distance69.2 ± 0.4 ly
(21.2 ± 0.1 pc)
Absolute magnitude (MV)3.40[2]
17 Cyg A
Radius0.95–1.1[5] R
Luminosity3.66[6] L
Surface gravity (log g)4.262[6] cgs
Temperature6,455[6] K
Metallicity [Fe/H]0.027[6] dex
Rotational velocity (v sin i)9[2] km/s
Age2.8[7] Gyr
Other designations
17 Cyg, BD+33 3587, GJ 9670, HD 187013, HIP 97295, HR 7534, SAO 68827.[8]
Database references

17 Cygni is the Flamsteed designation for a binary star system in the northern constellation of Cygnus. It has an apparent visual magnitude of 5.00,[2] so, according to the Bortle scale, it is visible from suburban skies at night. Measurements made with the Hipparcos spacecraft show an annual parallax shift of 0.04710″,[1] which is equivalent to a distance of around 69.2 ly (21.2 pc) from the Sun.

The stellar classification of the primary star is F7 V,[2] which means it is a main sequence star like the Sun. It is some 2.8[7] billion years old and shines with 3.66[6] times the Sun's luminosity. The effective temperature of the stellar atmosphere is 6,455[6] K, giving it the yellow-white hued glow of an F-type star.[9]

At an angular separation of 791.40 arcseconds is a proper motion companion with a classification of M0.4, indicating this is a red dwarf star. At the estimated distance of the pair, this is equal to a projected separation of 16,320 AU.[3] Although the CCDM lists four other companions, these are not associated with the pair.[10]


  1. ^ a b c d e f 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 d e f g Takeda, Yoichi; et al. (February 2005), "High-Dispersion Spectra Collection of Nearby F--K Stars at Okayama Astrophysical Observatory: A Basis for Spectroscopic Abundance Standards", Publications of the Astronomical Society of Japan, 57 (1): 13–25, Bibcode:2005PASJ...57...13T, doi:10.1093/pasj/57.1.13. 
  3. ^ a b Dhital, Saurav; et al. (June 2010), "Sloan Low-mass Wide Pairs of Kinematically Equivalent Stars (SLoWPoKES): A Catalog of Very Wide, Low-mass Pairs", The Astronomical Journal, 139 (6): 2566–2586, arXiv:1004.2755Freely accessible, Bibcode:2010AJ....139.2566D, doi:10.1088/0004-6256/139/6/2566. 
  4. ^ Nordström, B.; et al. (May 2004), "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14,000 F and G dwarfs", Astronomy and Astrophysics, 418: 989–1019, arXiv:astro-ph/0405198Freely accessible, Bibcode:2004A&A...418..989N, doi:10.1051/0004-6361:20035959. 
  5. ^ Pasinetti-Fracassini, L. E.; et al. (February 2001), "Catalogue of Stellar Diameters (CADARS)", Astronomy and Astrophysics, 367: 521–524, arXiv:astro-ph/0012289Freely accessible, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451. 
  6. ^ a b c d e f Takeda, Yoichi (April 2007), "Fundamental Parameters and Elemental Abundances of 160 F-G-K Stars Based on OAO Spectrum Database", Publications of the Astronomical Society of Japan, 59 (2): 335–356, Bibcode:2007PASJ...59..335T, doi:10.1093/pasj/59.2.335. 
  7. ^ a b Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982Freely accessible, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191. 
  8. ^ "* 17 Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2013-10-26. 
  9. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on March 10, 2012, retrieved 2012-01-16. 
  10. ^ Phillips, N. M.; et al. (April 2010), "Target selection for the SUNS and DEBRIS surveys for debris discs in the solar neighbourhood", Monthly Notices of the Royal Astronomical Society, 403 (3): 1089–1101, arXiv:0911.3426Freely accessible, Bibcode:2010MNRAS.403.1089P, doi:10.1111/j.1365-2966.2009.15641.x.  See the note for F094.

Coordinates: Sky map 19h 46m 25.60s, +33° 43′ 39.35″