Upsilon Aquilae

Upsilon Aquilae, Latinized from υ Aquilae, is the Bayer designation for a star in the equatorial constellation of Aquila. With an apparent visual magnitude of +5.91[4] it is a faint star but visible to the naked eye from suburban skies. It has an annual parallax shift of 18.65 milliarcsecond,[1] indicating a distance of around 175 light-years (54 parsecs).

Upsilon Aquilae
Location of υ Aquilae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila
Right ascension  19h 45m 39.94763s[1]
Declination +07° 36′ 47.3717″[1]
Apparent magnitude (V) +5.889[2]
Characteristics
Spectral type A3 IV[3]
U−B color index +0.09[4]
B−V color index +0.18[4]
Astrometry
Radial velocity (Rv)–29.9[5] km/s
Proper motion (μ) RA: +54.10[1] mas/yr
Dec.: +0.50[1] mas/yr
Parallax (π)18.65 ± 0.41[1] mas
Distance175 ± 4 ly
(54 ± 1 pc)
Absolute magnitude (MV)+2.24[6]
Details
Luminosity10.5[6] L☉
Surface gravity (log g)4.21[2] cgs
Temperature7,906[2] K
Metallicity [Fe/H]–0.05[2] dex
Rotational velocity (v sin i)42[7] km/s
Other designations
υ Aql, 49 Aquilae, BD+07° 4210, HD 186689, HIP 97229, HR 7519, SAO 125032.[8]
Database references
SIMBADdata

Upsilon Aquilae is a subgiant star with a stellar classification of A3 IV.[3] The outer atmosphere is radiating energy into space with 10.5[6] times the Sun's luminosity at an effective temperature of 7,906 K,[2] which gives it the white-hot glow of an A-type star. It is spinning relatively quickly with a projected rotational velocity of 42 km/s.[7]

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.
  2. Soubiran, C.; et al. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics, 515: A111, arXiv:1004.1069, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247.
  3. 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. 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.
  5. Wilson, Ralph Elmer (1953), "General catalogue of stellar radial velocities", Washington, Carnegie Institution of Washington: 0, Bibcode:1953GCRV..C......0W.
  6. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015.
  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/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224.
  8. "* ups Aql". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-21.
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