33 Cygni
Single star in the constellation Cygnus
33 Cygni is a single[ 7] star located 159 light years away in the northern constellation Cygnus . It is visible to the naked eye as a white-hued star with an apparent visual magnitude of 4.28.[ 2] The star is moving closer to the Earth with a heliocentric radial velocity of −16 km/s.[ 5] Eggen (1995) listed it as a proper motion candidate for membership in the IC 2391 supercluster.[ 9]
This star has a stellar classification of A3 IV–Vn,[ 4] showing a spectrum with traits intermediate between an A-type main-sequence star and an evolving subgiant star . The 'n' suffix indicates "nebulous" absorption lines due to rapid rotation. It is about 400[ 7] million years old with a high projected rotational velocity of 243 km/s.[ 3] This rate of spin is giving the star an oblate shape with a pronounced equatorial bulge that is an estimated 28% wider than the polar radius.[ 10]
33 Cyg has 2.33[ 3] times the mass of the Sun and 2.76[ 6] times the Sun's radius . The star is radiating 44 times the Sun's luminosity from its photosphere at an effective temperature of 8,395 K.[ 3] It displays an infrared excess that suggests an orbiting debris disk with a temperature of 500 K at a mean distance of 1.80 AU from the host star.[ 6]
References
^ a b c d e van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics , 474 (2): 653–664, arXiv :0708.1752 , Bibcode :2007A&A...474..653V , doi :10.1051/0004-6361:20078357 , S2CID 18759600 .
^ a b c d Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters , 38 (5): 331, arXiv :1108.4971 , Bibcode :2012AstL...38..331A , doi :10.1134/S1063773712050015 , S2CID 119257644 .
^ a b c d e Zorec, J.; et al. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy and Astrophysics , 537 : A120, arXiv :1201.2052 , Bibcode :2012A&A...537A.120Z , doi :10.1051/0004-6361/201117691 , S2CID 55586789 .
^ a b Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal , 74 : 375–406, Bibcode :1969AJ.....74..375C , doi :10.1086/110819 .
^ a b Becker, Juliette C.; et al. (April 2015), "Extracting Radial Velocities of A- and B-type Stars from Echelle Spectrograph Calibration Spectra", The Astrophysical Journal Supplement Series , 217 (2): 13, arXiv :1503.03874 , Bibcode :2015ApJS..217...29B , doi :10.1088/0067-0049/217/2/29 , S2CID 33968873 , 29.
^ a b c Cotten, Tara H.; Song, Inseok (July 2016), "A Comprehensive Census of Nearby Infrared Excess Stars", The Astrophysical Journal Supplement Series , 225 (1): 24, arXiv :1606.01134 , Bibcode :2016ApJS..225...15C , doi :10.3847/0067-0049/225/1/15 , S2CID 118438871 , 15.
^ a b c De Rosa, R. J.; et al. (2014), "The VAST Survey - III. The multiplicity of A-type stars within 75 pc", Monthly Notices of the Royal Astronomical Society , 437 (2): 1216, arXiv :1311.7141 , Bibcode :2014MNRAS.437.1216D , doi :10.1093/mnras/stt1932 , S2CID 88503488 .
^ "33 Cyg" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2019-01-14 .
^ Eggen, Olin J. (December 1995), "Reality Tests of Superclusters in the Young Disk Population", Astronomical Journal , 110 : 2862, Bibcode :1995AJ....110.2862E , doi :10.1086/117734 .
^ van Belle, Gerard T. (March 2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review , 20 (1): 51, arXiv :1204.2572 , Bibcode :2012A&ARv..20...51V , doi :10.1007/s00159-012-0051-2 , S2CID 119273474 .