Astronomy:8 Cygni

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Short description: Star in the constellation Cygnus
8 Cygni
Observation data
Equinox J2000.0]] (ICRS)
Constellation Cygnus
Right ascension  19h 31m 46.32184s[1]
Declination +34° 27′ 10.6874″[1]
Apparent magnitude (V) 4.75[2]
Characteristics
Spectral type B3 IV[3]
B−V color index −0.155[2]
Astrometry
Radial velocity (Rv)−21.20±0.1[4] km/s
Proper motion (μ) RA: 1.16[1] mas/yr
Dec.: −3.47[1] mas/yr
Parallax (π)3.79 ± 0.16[1] mas
Distance860 ± 40 ly
(260 ± 10 pc)
Details
Mass6.40[5] M
Radius6.50[5] R
Luminosity2,512[5] L
Surface gravity (log g)3.62[5] cgs
Temperature16,100[5] K
Metallicity [Fe/H]+0.25[5] dex
Rotational velocity (v sin i)15[6] km/s
Other designations
8 Cygni, BD+34° 3590, HD 184171, HIP 96052, HR 7426, SAO 68447.
Database references
SIMBADdata

8 Cygni is a single[7] star in the northern constellation of Cygnus. Based upon its parallax of 3.79 mas,[1] it is approximately 860 light-years (260 parsecs) away from Earth. It is visible to the naked eye as a faint, bluish-white hued star with an apparent visual magnitude of about 4.7.[2] The star is moving closer to the Earth with a heliocentric radial velocity of −21 km/s.[4]

This is an aging subgiant star, as indicated by its spectral type of B3IV.[3] Its effective temperature of 16,100 K fits into the normal range of B-type stars: 11,000 to 25,000 K. 8 Cygni is about twice as hot as the Sun, and it is six times larger and many times brighter in comparison.[5] The elemental abundances are near solar.[8]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode2007A&A...474..653V. http://www.aanda.org/index.php?option=com_article&access=bibcode&Itemid=129&bibcode=2007A%2526A...474..653VFUL. 
  2. 2.0 2.1 2.2 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode1986EgUBV........0M. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1986EgUBV........0M&db_key=AST&nosetcookie=1. 
  3. 3.0 3.1 Lesh, Janet Rountree (December 1968), "The Kinematics of the Gould Belt: an Expanding Group?", Astrophysical Journal Supplement 17: 371, doi:10.1086/190179, Bibcode1968ApJS...17..371L 
  4. 4.0 4.1 Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode2006AstL...32..759G. 
  5. 5.0 5.1 5.2 5.3 5.4 5.5 5.6 Challouf, M. et al. (2014), "Improving the surface brightness-color relation for early-type stars using optical interferometry⋆", Astronomy & Astrophysics 570: A104, doi:10.1051/0004-6361/201423772, Bibcode2014A&A...570A.104C. 
  6. Abt, Helmut A.; Levato, Hugo; Grosso, Monica (2002). "Rotational Velocities of B Stars". The Astrophysical Journal 573 (1): 359–365. doi:10.1086/340590. Bibcode2002ApJ...573..359A. 
  7. 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode2008MNRAS.389..869E. 
  8. Adelman, Saul J. (June 1998). "Elemental abundance analyses with DAO spectrograms - XIX. The superficially normal B stars zeta Draconis, epsilon Lyrae, 8 Cygni and 22 Cygni". Monthly Notices of the Royal Astronomical Society 296 (4): 856–862. doi:10.1046/j.1365-8711.1998.01426.x. Bibcode1998MNRAS.296..856A.