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Quadruple star system in the constellation of Andromeda
HD 225218 is a quadruple star system in the northern constellation of Andromeda . The primary component, HD 225218 A, is a giant star with a stellar classification of B9III,[ 4] apparent magnitude of 6.16,[ 2] Lambda Boötis star .[ 9] angular separation of 5.2″ along a position angle of 171°.[ 2] binary star system through interferometry , with the two components separated by 0.165″. The pair, HD 225218 Aa and Ab, orbit each other with a period of about 70 years and an eccentricity of 0.515.[ 6] spectroscopic binary .[ 9]
^ a b c d e Brown, A. G. A. ; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties" . Astronomy & Astrophysics 649 : A1. arXiv :2012.01533 Bibcode :2021A&A...649A...1G . doi :10.1051/0004-6361/202039657 S2CID 227254300 . (Erratum: doi :10.1051/0004-6361/202039657e ) . Gaia EDR3 record for this source at VizieR .^ a b c d Mason, Brian D.; et al. (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 ^ a b c d e Brown, A. G. A. ; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties" . Astronomy & Astrophysics 649 : A1. arXiv :2012.01533 Bibcode :2021A&A...649A...1G . doi :10.1051/0004-6361/202039657 S2CID 227254300 . (Erratum: doi :10.1051/0004-6361/202039657e ) . Gaia EDR3 record for this source at VizieR .^ 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 ^ Wilson, R. E. (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication , Carnegie Institute of Washington, D.C., Bibcode :1953GCRV..C......0W ^ a b Malkov, O. Yu.; et al. (2012), "Dynamical Masses of a Selected Sample of Orbital Binaries", Astronomy & Astrophysics , 546 : 5, Bibcode :2012A&A...546A..69M , doi :10.1051/0004-6361/201219774 ^ a b McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society , 427 (1): 343–57, arXiv :1208.2037 Bibcode :2012MNRAS.427..343M , doi :10.1111/j.1365-2966.2012.21873.x S2CID 118665352 ^ Abt, Helmut A.; et al. (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal , 573 (1): 359–365, Bibcode :2002ApJ...573..359A , doi :10.1086/340590 ^ a b Faraggiana, Rosanna; Bonifacio, Piercarlo (September 1999), "How many lambda Bootis stars are binaries?", Astronomy and Astrophysics , 349 : 521–531, arXiv :astro-ph/9906009 Bibcode :1999A&A...349..521F
