57 Aquilae

57 Aquilae (abbreviated 57 Aql) is a double star in the constellation of Aquila. 57 Aquilae is its Flamsteed designation. The primary star has an apparent visual magnitude of 5.70, while the secondary is magnitude 6.48.[2] The pair have an angular separation of 35.624 arcseconds and probably form a wide binary star system.[7] The estimated distance of the first component is 480 light-years (150 parsecs), while the second is at 510 light-years (160 parsecs). However, the margin of errors for their respective distance estimates overlap,[1] indicating a probability that they are actually located much closer to each other. Both stars are massive, B-type main sequence stars with rapid rotation rates.[3]

57 Aquilae
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila
57 Aql A
Right ascension 19h 54m 37.65152s[1]
Declination –08° 13′ 38.2390″[1]
Apparent magnitude (V) 5.70[2]
57 Aql B
Right ascension 19h 54m 38.06165s[1]
Declination –08° 14′ 13.3762″[1]
Apparent magnitude (V) 6.48[2]
Characteristics
Spectral type B7 Vn + B8 V[3]
U−B color index –0.49/–0.27[2]
B−V color index –0.08/–0.04[2]
Astrometry
57 Aql A
Radial velocity (Rv)–6[4] km/s
Proper motion (μ) RA: +6.61[1] mas/yr
Dec.: –25.75[1] mas/yr
Parallax (π)6.76 ± 0.37 mas[1]
Distance480 ± 30 ly
(148 ± 8 pc)
57 Aql B
Radial velocity (Rv)–5[4] km/s
Proper motion (μ) RA: +2.13 mas/yr
Dec.: –30.77 mas/yr
Parallax (π)6.42 ± 0.58 mas[1]
Distance510 ± 50 ly
(160 ± 10 pc)
Details
57 Aql A
Rotational velocity (v sin i)190[3] km/s
57 Aql B
Rotational velocity (v sin i)160[3] km/s
Other designations
57 Aql A: BD–08 5154, HD 188293, HIP 97966, HR 7593, SAO 143898.[5]
57 Aql B: BD–08 5155, HD 188294, HIP 97967, HR 7594, SAO 143899.[6]
Database references
SIMBAD57 Aql
57 Aql A
57 Aql B

References
  1. 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, S2CID 18759600.
  2. Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
  3. Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590.
  4. Wilson, Ralph Elmer (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication, Washington: Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
  5. "HR 7593 -- Star in double system", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-25.
  6. "HR 7594 -- Star in double system", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-25.
  7. 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, S2CID 14878976.


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