Chi Aquilae

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Chi Aquilae
Diagram showing star positions and boundaries of the Aquila constellation and its surroundings
Cercle rouge 100%.svg

Location of χ Aquarii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila
Right ascension 19h 42m 34.00828s[1]
Declination +11° 49′ 35.7023″[1]
Apparent magnitude (V) 5.292[2] (5.80/6.68)[3]
Spectral type G2 Ib-II + B5 V[3]
U−B color index -0.04[4]
B−V color index +0.57[4]
Radial velocity (Rv) -19.2[2] km/s
Proper motion (μ) RA: 1.75[1] mas/yr
Dec.: -10.11[1] mas/yr
Parallax (π) 3.82 ± 0.51[1] mas
Distance approx. 900 ly
(approx. 260 pc)
Other designations
47 Aquilae, ADS 12808, BD+11 3955, HD 186203, HIP 96957, HR 7497, SAO 105168.[4]

Chi Aquilae (χ Aql, χ Aquilae) is the Bayer designation for a binary star[3] in the equatorial constellation of Aquila, the eagle. This system is bright enough to be seen with the naked eye at a combined visual magnitude of +5.29.[2] Based upon parallax measurements made during the Hipparcos mission, Chi Aquilae is at a distance of approximately 900 light-years (280 parsecs) from Earth.[1]

The brighter member of Chi Aquilae is yellow-hued G-type star with a stellar classification of G2 Ib-II and an apparent magnitude of 5.80. A luminosity class of Ib-II indicates the spectrum lies midway between that of a bright giant and a supergiant star. The companion is a white-hued A-type main sequence star with a classification of B5 V and an apparent magnitude of 6.68.[3] As of 2004, the secondary is located at an angular separation of 0.418 arcseconds along a position angle of 76.7° from the primary.[5]


  1. ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752free to read, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c Nordström, B.; et al. (May 2004), "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14 000 F and G dwarfs", Astronomy and Astrophysics, 418: 989–1019, arXiv:astro-ph/0405198free to read, Bibcode:2004A&A...418..989N, doi:10.1051/0004-6361:20035959. 
  3. ^ a b c d Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878free to read, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x. 
  4. ^ a b c "chi Aql -- Star", SIMBAD Astronomical Object Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-05. 
  5. ^ Scardia, M.; et al. (April 2006), "Speckle observations with PISCO in Merate - II. Astrometric measurements of visual binaries in 2004", Monthly Notices of the Royal Astronomical Society, 367 (3): 1170–1180, Bibcode:2006MNRAS.367.1170S, doi:10.1111/j.1365-2966.2006.10035.x. 

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