19 Aquilae

19 Aquilae is a single[12] star located 142 light-years (44 parsecs) away from the Sun in the equatorial constellation of Aquila. 19 Aquilae is the Flamsteed designation. It is visible to the naked eye as a dim, yellow-white hued star with an apparent visual magnitude of 5.23.[2] The star is moving closer to the Earth with a heliocentric radial velocity of −46.7 km/s.[7]

19 Aquilae

Image captured from Mount Laguna, California
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Aquila
Right ascension 19h 08m 59.90684s[1]
Declination +06° 04′ 23.4857″[1]
Apparent magnitude (V) 5.227[2]
Characteristics
Spectral type F0 III-IV[3]
Apparent magnitude (U) 5.59±0.010[4]
Apparent magnitude (B) 5.57±0.007[5]
Apparent magnitude (V) 5.23±0.009[5]
U−B color index +0.020[2]
B−V color index +0.345[2]
Variable type suspected γ Dor[6]
Astrometry
Radial velocity (Rv)−46.7[7] km/s
Proper motion (μ) RA: −5.485[1] mas/yr
Dec.: −73.785[1] mas/yr
Parallax (π)22.9563 ± 0.2397[1] mas
Distance142 ± 1 ly
(43.6 ± 0.5 pc)
Absolute magnitude (MV)1.94[8]
Details
Mass1.54[9] M☉
Radius2.50+0.25
−0.05[1] R☉
Luminosity12.8±0.2[1] L☉
Surface gravity (log g)4.13[3] cgs
Temperature6,784±53[9] K
Metallicity [Fe/H]+0.03[3] dex
Rotational velocity (v sin i)57.0[10] km/s
Age2.25[9] Gyr
Other designations
19 Sge, BD+5°4040, FK5 3530, HD 178596, HIP 94068, HR 7266, SAO 124318[11]
Database references
SIMBADdata

This object has a stellar classification of F0 III-IV,[3] with the luminosity class matching an evolving star transitioning from the subgiant to a giant stage. Poretti et al. (2003) list it as a suspected Gamma Doradus variable, and it is located near the cooler end of the instability strip on the Hertzsprung–Russell diagram.[6] These spatial coordinates are a source of X-ray emission, which is most likely coming from the star.[13]

19 Aquilae is an estimated 2.25[9] billion years old with a moderately high rate of spin, showing a projected rotational velocity of 57.0 km/s.[10] It has 1.54[9] times the mass of the Sun and 2.50[1] times the Sun's radius. The star is radiating 12.8[1] times the luminosity of the Sun from its photosphere at an effective temperature of 6,784 K.[9]

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. Oja, T. (1986). "UBV photometry of stars whose positions are accurately known. III". Astronomy and Astrophysics Supplement Series. 65 (2): 405–4. Bibcode:1986A&AS...65..405O.
  3. Balachandran, Suchitra (May 1, 1990). "Lithium depletion and rotation in main-sequence stars". Astrophysical Journal, Part 1. 354: 310–332. Bibcode:1990ApJ...354..310B. doi:10.1086/168691.
  4. Oja, T. (1984). "UBV photometry of stars whose positions are accurately known". Astronomy and Astrophysics Supplement Series. 57: 357. Bibcode:1984A&AS...57..357O.
  5. Oja, T. (September 1993). "UBV photometry of stars whose positions are accurately known. VII". Astronomy and Astrophysics Supplement Series. 100 (3): 591–592. Bibcode:1993A&AS..100..591O. ISSN 0365-0138.
  6. Poretti, E.; et al. (2003). "Preparing the COROT space mission: Incidence and characterisation of pulsation in the lower instability strip". Astronomy and Astrophysics. 406: 203. arXiv:astro-ph/0304422. Bibcode:2003A&A...406..203P. doi:10.1051/0004-6361:20030711.
  7. Wielen, R.; et al. (1999). "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions". Veröffentlichungen Astronomisches Rechen-Institut Heidelberg. Astronomisches Rechen-Institut Heidelberg. 35 (35). Bibcode:1999VeARI..35....1W.
  8. Holmberg, J.; et al. (July 2009). "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics". Astronomy and Astrophysics. 501 (3): 941–947. arXiv:0811.3982. Bibcode:2009A&A...501..941H. doi:10.1051/0004-6361/200811191.
  9. Luck, R. Earle (2015). "Abundances in the Local Region. I. G and K Giants". Astronomical Journal. 150 (3): 88. arXiv:1507.01466. Bibcode:2015AJ....150...88L. doi:10.1088/0004-6256/150/3/88.
  10. Schröder, C.; Reiners, A.; Schmitt, J. H. M. M. (January 2009). "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo" (PDF). Astronomy and Astrophysics. 493 (3): 1099–1107. Bibcode:2009A&A...493.1099S. doi:10.1051/0004-6361:200810377. Retrieved 2019-06-01.
  11. "19 Aql". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-05-30.
  12. Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x.
  13. Haakonsen, Christian Bernt; Rutledge, Robert E. (September 2009). "XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources". The Astrophysical Journal Supplement. 184 (1): 138–151. arXiv:0910.3229. Bibcode:2009ApJS..184..138H. doi:10.1088/0067-0049/184/1/138.
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