97 Aquarii

From Wikipedia, the free encyclopedia
Jump to: navigation, search
97 Aquarii
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 23h 22m 39.17113s[1]
Declination –15° 02′ 21.6245″[1]
Apparent magnitude (V) 5.20[2] (5.59/6.72)[3]
Spectral type A2 V + A7 V[4]
U−B color index +0.10[2]
B−V color index +0.20[2]
Radial velocity (Rv) –12[5] km/s
Proper motion (μ) RA: +117.00[1] mas/yr
Dec.: +16.48[1] mas/yr
Parallax (π) 15.30 ± 0.79[1] mas
Distance 210 ± 10 ly
(65 ± 3 pc)
Period (P) 64.62 yr
Semi-major axis (a) 0.408"
Eccentricity (e) 0.140
Inclination (i) 77.6°
Longitude of the node (Ω) 276.3°
Periastron epoch (T) 1941.29
Argument of periastron (ω)
Rotational velocity (v sin i) 175[7] km/s
Other designations
BD–15 6406, HD 220278, HIP 115404, HR 8890, SAO 165658.[8]

97 Aquarii (abbreviated 97 Aqr) is a binary star system in the equatorial constellation of Aquarius. 97 Aquarii is the Flamsteed designation. The combined apparent visual magnitude of the system is 5.20;[2] the brighter star is magnitude 5.59 while the companion is magnitude 6.72.[3] Based upon an annual parallax shift of 15.30 milliarcseconds,[1] this system is at a distance of around 210 light-years (64 parsecs) from Earth.

The two stars in this system orbit each other over a period of 64.62 years at an eccentricity of 0.14.[3] Both are A-type main sequence stars; the primary has a stellar classification of A2 V while its companion is A7 V.[4] Their composite spectrum shows the properties of a Lambda Boötis star, which means it displays peculiar abundances of certain elements.[9]


  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 d Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N. 
  3. ^ a b c 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 Christy, James W.; Walker, R. L., Jr. (October 1969), "MK Classification of 142 Visual Binaries", Publications of the Astronomical Society of the Pacific, 81 (482): 643, Bibcode:1969PASP...81..643C, doi:10.1086/128831 
  5. ^ Wilson, Ralph Elmer (1953). General Catalogue of Stellar Radial Velocities. Washington: Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W. 
  6. ^ "New orbits", International Astronomical Union Commission 26 (Double Stars) (Information Circular No. 139): 1–2, 1999, Bibcode:1999IAUDS.139....1. 
  7. ^ Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785free to read, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224. 
  8. ^ "97 Aqr -- Star", SIMBAD Astronomical Object Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-17 
  9. ^ Gerbaldi, M.; Faraggiana, R.; Lai, O. (December 2003), "The heterogeneous class of lambda Bootis stars", Astronomy and Astrophysics, 412: 447–464, Bibcode:2003A&A...412..447G, doi:10.1051/0004-6361:20031472. 

External links[edit]