HD 225218

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HD 225218
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 00h 04m 36.58707s[1]
Declination +42° 05′ 33.1118″[1]
Apparent magnitude (V) 6.133 (6.16 + 9.65)[2]
Spectral type B9III[3] + F0V:
U−B color index 0.14
B−V color index 0.15
Radial velocity (Rv) −8.0[4] km/s
Proper motion (μ) RA: −11.35±0.42[1] mas/yr
Dec.: −12.64±0.36[1] mas/yr
Parallax (π) 2.59 ± 0.56[1] mas
Distance approx. 1,300 ly
(approx. 390 pc)
Period (P) 70.12 yr
Semi-major axis (a) 0.165″
Eccentricity (e) 0.515
Luminosity 394[6] L
Temperature 7,611[6] K
Rotation 25[7]
Other designations
BD+41 4933, HD 225218, HIP 365, HR 9105, NSV 15012, SAO 36037, WDS J00046+4206.
Database references
Database references

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,[3] an apparent magnitude of 6.16,[2] and is a candidate Lambda Boötis star.[8] It has a fainter, magnitude 9.65 companion, HD 225218 B, at an angular separation of 5.2″ along a position angle of 171°.[2] The primary itself has been identified as a 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.[5] Component B is likewise a spectroscopic binary.[8]


  1. ^ a b c d e van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752Freely accessible, doi:10.1051/0004-6361:20078357 Vizier catalog entry
  2. ^ a b c 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 
  3. ^ 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 
  4. ^ Wilson, R. E. (1953), General Catalogue of Stellar Radial Velocities, Carnegie Institute of Washington, D.C., Bibcode:1953GCRV..C......0W 
  5. ^ 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, A69 
  6. ^ 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, Bibcode:2012MNRAS.427..343M, arXiv:1208.2037Freely accessible, doi:10.1111/j.1365-2966.2012.21873.x 
  7. ^ 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 
  8. ^ a b Faraggiana, Rosanna; Bonifacio, Piercarlo (September 1999), "How many lambda Bootis stars are binaries?", Astronomy and Astrophysics, 349: 521–531, Bibcode:1999A&A...349..521F, arXiv:astro-ph/9906009Freely accessible 

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