45 Aquilae

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45 Aquilae
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila
Right ascension 19h 40m 43.31286s[1]
Declination –00° 37′ 16.6538″[1]
Apparent magnitude (V) 5.656[2]
Characteristics
Spectral type A3 IV[3]
U−B color index +0.09[2]
B−V color index +0.11[2]
Astrometry
Radial velocity (Rv) -46[4] km/s
Proper motion (μ) RA: 8.42[1] mas/yr
Dec.: 23.05[1] mas/yr
Parallax (π) 9.26 ± 0.70[1] mas
Distance 350 ± 30 ly
(108 ± 8 pc)
Orbit[5]
Primary 5 Aql Aa
Companion 5 Aql Ab
Period (P) 20.31 ± 0.17 yr
Semi-major axis (a) 0.0850 ± 0.0020"
Eccentricity (e) 0.054 ± 0.047
Inclination (i) 158.3 ± 7.9°
Longitude of the node (Ω) 202.0 ± 15.0°
Periastron epoch (T) 1996.06 ± 0.92
Argument of periastron (ω)
(secondary)
346.0 ± 25.0°
Details
Rotational velocity (v sin i) 75[6] km/s
Other designations
BD-00 3813, FK5 3573, HD 185762, HIP 96807, HR 7480, SAO 14367, WDS J19407-0037.[7]

45 Aquilae is the Flamsteed designation for a triple star system in the equatorial constellation of Aquila. It is located 350 light-years (110 parsecs) away from Earth, give or take a 30 light-year margin of error, and has an apparent visual magnitude of 5.7.[2]

Based upon a stellar classification of A3 IV,[3] the primary component of this system is a subgiant star that is in the process of evolving away from the main sequence. It has an orbiting companion with a period of 20.31 years and an eccentricity of 0.054. At an angular separation of 42.2 arcseconds from this pair is a 12.7 magnitude tertiary companion.[8]

References[edit]

  1. ^ a b c d e van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, arXiv:0708.1752, 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 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, Ralph Elmer (1953), General catalogue of stellar radial velocities, Carnegie Institution of Washington, Bibcode:1953QB901.W495...... 
  5. ^ Mason, Brian D.; Hartkopf, William I.; Tokovinin, Andrei (September 2010), "Binary Star Orbits. IV. Orbits of 18 Southern Interferometric Pairs", The Astronomical Journal 140 (3): 735–743, Bibcode:2010AJ....140..735M, doi:10.1088/0004-6256/140/3/735. 
  6. ^ Royer, F. et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics 393: 897–911, arXiv:astro-ph/0205255, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943. 
  7. ^ "45 Aql -- Star in double system", SIMBAD (Centre de Données astronomiques de Strasbourg), retrieved 2012-07-26. 
  8. ^ 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:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. 

External links[edit]