Astronomy:Kappa Aquilae

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Short description: Star in the constellation Aquila
κ Aquilae
Location of κ Aquilae (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Aquila[1]
Right ascension  19h 36m 53.449s[2]
Declination −07° 01′ 38.92″[2]
Apparent magnitude (V) +4.957[3]
Characteristics
Spectral type B0.5 III[4]
U−B color index −0.861[3]
B−V color index −0.028[3]
Astrometry
Radial velocity (Rv)−19.4±4.2[5] km/s
Proper motion (μ) RA: +0.974[2] mas/yr
Dec.: −3.241[2] mas/yr
Parallax (π)1.9758 ± 0.1533[2] mas
Distance1,700 ± 100 ly
(510 ± 40 pc)
Absolute magnitude (MV)−3.60[1]
Details
Mass15.50±0.61[6] M☉
Radius12.5[7] R☉
Luminosity52,630[6] L☉
Surface gravity (log g)3.5[8] cgs
Temperature26,500[6] K
Metallicity [Fe/H]−0.16[1] dex
Rotational velocity (v sin i)265[9] km/s
Age11.1±0.5[4] Myr
Other designations
κ Aquilae, Kappa Aql, κ Aql, 39 Aquilae, BD−07 5006, FK5 737, GC 27107, HD 184915, HIP 96483, HR 7446, SAO 143600, PPM 203088[10]
Database references
SIMBADdata

Kappa Aquilae is a star in the equatorial constellation of Aquila. Its name is a Bayer designation that is Latinized from κ Aquilae, and abbreviated Kappa Aql or κ Aql. This is a faint star with an apparent visual magnitude of +4.957,[3] which is bright enough to be seen with the naked eye in dark suburban skies. The annual parallax is only 1.98 mas,[2] which equates to a distance of approximately 1,700 light-years (520 parsecs) from Earth (with a 6% margin of error).

The spectrum of Kappa Aquilae matches a stellar classification of B0.5 III,[4] where the luminosity class of III is typically associated with evolved giant stars. It is spinning rapidly with a projected rotational velocity of 265 km/s[9] and in the past has been classified as a Be star, despite the lack of an 'e' in the class.[11] However, the weak emission is most likely coming from the outflow of a hot stellar wind rather than a decretion disk.[12] This is a star with 15.50 times the Sun's mass[6] and 12.5 times the radius of the Sun.[7] Massive stars like this are luminous; it is radiating 52,630 times the Sun's luminosity[6] from its outer atmosphere with an effective temperature of 26,500 K,[6] giving it the intense blue-white glow of a B-type star. It is only 11 million years of age.[4]

Etymology

In Chinese, 右旗 (Yòu Qí), meaning Right Flag, refers to an asterism consisting of κ Aquilae, μ Aquilae, σ Aquilae, δ Aquilae, ν Aquilae, 42 Aquilae, ι Aquilae, HD 184701 and 56 Aquilae.[13] Consequently, the Chinese name for κ Aquilae itself is 右旗八 (Yòu Qí bā, English: the Eighth Star of Right Flag.)[14]

This star, together with η Aql, θ Aql, δ Aql, ι Aql and λ Aql were once part of the now-obsolete constellation Antinous.[15]

References

  1. ↑ 1.0 1.1 1.2 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 3.2 3.3 Gutierrez-Moreno, Adelina et al. (1966), "A System of photometric standards", Publications of the Department of Astronomy University of Chile (Publicaciones Universidad de Chile, Department de Astronomy) 1: 1–17, Bibcode: 1966PDAUC...1....1G. 
  4. ↑ 4.0 4.1 4.2 4.3 Tetzlaff, N. et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode: 2011MNRAS.410..190T. 
  5. ↑ Wielen, R. et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg (Astronomisches Rechen-Institut Heidelberg) 35 (35): 1, Bibcode: 1999VeARI..35....1W. 
  6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Hohle, M. M. et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten 331 (4): 349, doi:10.1002/asna.200911355, Bibcode: 2010AN....331..349H. 
  7. ↑ 7.0 7.1 Underhill, A. B. et al. (November 1979), "Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars", Monthly Notices of the Royal Astronomical Society 189 (3): 601–605, doi:10.1093/mnras/189.3.601, Bibcode: 1979MNRAS.189..601U. 
  8. ↑ Frémat, Y. et al. (September 2005), "Effects of gravitational darkening on the determination of fundamental parameters in fast-rotating B-type stars", Astronomy and Astrophysics 440 (1): 305–320, doi:10.1051/0004-6361:20042229, Bibcode: 2005A&A...440..305F. 
  9. ↑ 9.0 9.1 Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal 573 (1): 359–365, doi:10.1086/340590, Bibcode: 2002ApJ...573..359A. 
  10. ↑ "* kap Aql". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+kap+Aql. 
  11. ↑ Cote, J.; van Kerkwijk, M. H. (July 1993), "New bright Be stars and the Be star frequency", Astronomy and Astrophysics 274: 870–876, Bibcode: 1993A&A...274..870C. 
  12. ↑ Rivinius, Thomas et al. (October 2013), "Classical Be stars. Rapidly rotating B stars with viscous Keplerian decretion disks", The Astronomy and Astrophysics Review 21: id. 69, doi:10.1007/s00159-013-0069-0, Bibcode: 2013A&ARv..21...69R. 
  13. ↑ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  14. ↑ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 3 日
  15. ↑ Ridpath, Ian, "Antinous", Ian Ridpath's Star Tales, http://www.ianridpath.com/startales/antinous.html, retrieved 2025-03-18. 



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