Visual binary in the constellation Camelopardalis
HD 20104 (HR 967 ) is a visualbinary in the northerncircumpolar constellation Camelopardalis . The system has a combinedapparent magnitude of 6.41,[ 9] naked eye visibility. When resolved in a large telescope, HD 20104 appears to be a pair of 7th magnitudeA-type main-sequence stars with a separation of about″ [ 10] light years away,[ 6] Sun with a heliocentricradial velocity ofkm/s [ 5]
The system's stars have masses twice that of theSun [ 8] effective temperatures ranging from 8,100 to 8,700K ,[ 9] [ 11] L ☉ [ 11] projected rotational velocity ofkm/s [ 12] million years .[ 11]
^a b 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 . XHIP record for this object atVizieR .^a b c d e f Fabricius, C.; Høg, E.; Makarov, V. V.; Mason, B. D.; Wycoff, G. L.; Urban, S. E. (March 2002)."The Tycho double star catalogue" .Astronomy & Astrophysics .384 (1):180– 189.Bibcode :2002A&A...384..180F .doi :10.1051/0004-6361:20011822 ISSN 0004-6361 . ^a b Edwards, T. W. (April 1976)."MK classification for visual binary components" .The Astronomical Journal .81 : 245.Bibcode :1976AJ.....81..245E .doi :10.1086/111879 ISSN 0004-6256 . ^a b Haupt, H. F.; Schroll, A. (1974). "Photoelektrische Photometrie von Shell-Sternen".Astronomy and Astrophysics Supplement Series .15 :311– 319.Bibcode :1974A&AS...15..311H .ISSN 0365-0138 . ^a b Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities".Carnegie Institute Washington D.C. Publication : 0.Bibcode :1953GCRV..C......0W . ^a b c van Leeuwen, F. (November 2007)."Validation of the new Hipparcos reduction" .Astronomy & Astrophysics .474 (2):653– 664.arXiv :0708.1752 Bibcode :2007A&A...474..653V .doi :10.1051/0004-6361:20078357 ISSN 0004-6361 . ^ Heintz, W. D. (July 1998)."Observations of Double Stars. XVIII" .The Astrophysical Journal Supplement Series .117 (2):587– 598.Bibcode :1998ApJS..117..587H .doi :10.1086/313127 ^a b c Cvetkovic, Zorica; Ninkovic, S. (2010)."On the component masses of visual binaries" .Serbian Astronomical Journal .180 (180):71– 80.Bibcode :2010SerAJ.180...71C .doi :10.2298/SAJ1080071C ^a b Anders, F.; Khalatyan, A.; Chiappini, C.; Queiroz, A. B.; Santiago, B. X.; Jordi, C.; Girardi, L.; Brown, A. G. A.; Matijevič, G.; Monari, G.; Cantat-Gaudin, T.; Weiler, M.; Khan, S.; Miglio, A.; Carrillo, I.; Romero-Gómez, M.; Minchev, I.; de Jong, R. S.; Antoja, T.; Ramos, P.; Steinmetz, M.; Enke, H. (August 2019)."Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18" .Astronomy & Astrophysics .628 : A94.arXiv :1904.11302 Bibcode :2019A&A...628A..94A .doi :10.1051/0004-6361/201935765 ISSN 0004-6361 . ^ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (December 2001)."The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog" .The Astronomical Journal .122 (6):3466– 3471.Bibcode :2001AJ....122.3466M .doi :10.1086/323920 ISSN 0004-6256 . ^a b c Zorec, J.; Royer, F. (January 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 ISSN 0004-6361 .S2CID 55586789 . ^ Royer, F.; Zorec, J.; Gómez, A. E. (February 2007)."Rotational velocities of A-type stars: III. Velocity distributions" .Astronomy & Astrophysics .463 (2):671– 682.arXiv :astro-ph/0610785 Bibcode :2007A&A...463..671R .doi :10.1051/0004-6361:20065224 ISSN 0004-6361 .
