Astronomy:22 Cygni

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Short description: Star in the constellation Cygnus
22 Cygni
Observation data
Equinox J2000.0]] (ICRS)
Constellation Cygnus
Right ascension  19h 55m 51.75718s[1]
Declination +38° 29′ 12.154″[1]
Apparent magnitude (V) 4.95[2]
Characteristics
Spectral type B5 IV[3]
B−V color index −0.086±0.009[2]
Astrometry
Radial velocity (Rv)−14.8±2.2[4] km/s
Proper motion (μ) RA: +6.559[1] mas/yr
Dec.: −0.469[1] mas/yr
Parallax (π)3.0418 ± 0.2388[1] mas
Distance1,070 ± 80 ly
(330 ± 30 pc)
Absolute magnitude (MV)−3.18[2]
Orbit[5]
Period (P)78.2±0.4 d
Eccentricity (e)0.17±0.13
Periastron epoch (T)2443734.5±2.1 JD
Argument of periastron (ω)
(secondary)
139±11°
Semi-amplitude (K1)
(primary)
20.7±3.1 km/s
Details
22 Cyg A
Mass7.9±0.4[6] M
Radius5.6[7] R
Luminosity7,305[8] L
Surface gravity (log g)3.35[9] cgs
Temperature15,200[8] K
Rotational velocity (v sin i)30[10] km/s
Age37.3±4.2[6] Myr
Other designations
22 Cyg, BD+38°3817, HD 188892, HIP 98068, HR 7613, SAO 69101[11]
Database references
SIMBADdata

22 Cygni is a binary star system in the northern constellation of Cygnus. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.95.[2] The annual shift of 3.0 mas[1] yields a distance estimate of around 1,070 light years. It is moving closer to the Earth with a heliocentric radial velocity of −15 km/s.[4]

This is a single-lined spectroscopic binary with an orbital period of 78.2 days and an eccentricity of roughly 0.17.[5] The visible component has a stellar classification of B5 IV[3] that matches a B-type subgiant star. It is 37[6] million years old with a projected rotational velocity of 30[10] km/s and has an essentially solar metallicity, within the margin of error.[9] The star has eight[6] times the mass of the Sun and about 5.6[7] times the Sun's radius. It is radiating 7,305[8] times the Sun's luminosity from its photosphere at an effective temperature of 15,200 K.[8]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  2. 2.0 2.1 2.2 2.3 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  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 Abt, Helmut A. et al. (October 1990), "The Frequency and Formation Mechanism of B2--B5 Main-Sequence Binaries", Astrophysical Journal Supplement 74: 551, doi:10.1086/191508, Bibcode1990ApJS...74..551A. 
  6. 6.0 6.1 6.2 6.3 Tetzlaff, N. et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode2011MNRAS.410..190T. 
  7. 7.0 7.1 Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics 367: 521–524, doi:10.1051/0004-6361:20000451, Bibcode2001A&A...367..521P. 
  8. 8.0 8.1 8.2 8.3 Hohle, M. M. et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten 331 (4): 349, doi:10.1002/asna.200911355, Bibcode2010AN....331..349H. 
  9. 9.0 9.1 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. 
  10. 10.0 10.1 Abt, Helmut A. et al. (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal 573 (1): 359–365, doi:10.1086/340590, Bibcode2002ApJ...573..359A 
  11. "22 Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=22+Cyg.