21 Aquilae

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21 Aquilae
V1288AqlLightCurve.png
An ultraviolet band light curve for V1288 Aquilae, adapted from Veto (1980) [1]
Observation data
Epoch J2000       Equinox J2000
Constellation Aquila
Right ascension 19h 13m 42.70120s [2]
Declination +02° 17′ 37.3103″ [2]
Apparent magnitude  (V)5.06 - 5.16 [3]
Characteristics
Spectral type B8II-III(Hg?) [4]
U−B color index −0.399 [5]
B−V color index −0.065 [5]
Variable type α2 CVn [3]
Astrometry
Radial velocity (Rv)−5.2 [6]  km/s
Proper motion (μ)RA: +10.102 [2]   mas/yr
Dec.: −0.825 [2]   mas/yr
Parallax (π)4.7730 ± 0.1052  mas [2]
Distance 680 ± 20  ly
(210 ± 5  pc)
Absolute magnitude  (MV)−2.12 [7]
Details
Mass 6.7 [8]   M☉
Radius 6.2 [9]   R☉
Luminosity 704 [8]   L☉
Surface gravity (log g)3.95 [8]   cgs
Temperature 12,014 [8]   K
Metallicity [Fe/H]−0.20 [10]   dex
Rotation 9.3  d [11]
Rotational velocity (v sin i)17 [10]  km/s
Age 165 [12]   Myr
Other designations
21 Aql, V1288 Aql, BD+02°3824, FK5  3537, HD  179761, HIP  94477, HR  7287, SAO  124408, WDS J19137+0218A [13]
Database references
SIMBAD data

21 Aquilae is a solitary [14] variable star in the equatorial constellation of Aquila. It has the variable star designation V1288 Aql; 21 Aquilae is its Flamsteed designation. This object is visible to the naked eye as a dim, blue-white hued star with a baseline apparent visual magnitude of about 5.1. The star is located at a distance of around 680 light-years (210 parsecs ) from Earth, give or take a 20 light-year margin of error. It is moving closer to the Earth with a heliocentric radial velocity of –5 km/s. [6]

The stellar classification of this star is B8 II-III, with the luminosity class of II-III suggesting that the spectrum displays elements of both a giant star and a bright giant. It is a chemically peculiar star of the Mercury-Manganese type (CP3), [10] although some catalogues consider that status to be doubtful. [15] This is a probable Alpha2 Canum Venaticorum variable that ranges in visual magnitude from 5.06 down to 5.16. [3] The star is radiating 704 times the luminosity of the Sun from its photosphere at an effective temperature of 12,014  K ; this gives it the blue-white glow of a B-type star. [16]

21 Aquilae is catalogued as an optical double star, having a 12th magnitude companion 37″ away as of 2010. It was first identified as a double star by John Herschel. [17] The companion is a distant background object. [18]

Related Research Articles

<span class="mw-page-title-main">Eta Aquilae</span> Multiple star in the constellation Aquila

Eta Aquilae is a multiple star in the equatorial constellation of Aquila, the eagle. It was once part of the former constellation Antinous. Its apparent visual magnitude varies between 3.49 and 4.3, making it one of the brighter members of Aquila. Based upon parallax measurements made by the Gaia spacecraft on its third data release (DR3), this star is located at a distance of roughly 272 parsecs. The primary component is a Classical Cepheid variable.

<span class="mw-page-title-main">Nu Aquilae</span> Star in the constellation Aquila

Nu Aquilae, Latinized from ν Aquilae, is the Bayer designation for a double star in the constellation of Aquila that lies close to the celestial equator. It has an apparent visual magnitude of 4.72 and so is visible to the naked eye. Based upon an annual parallax shift of only 0.8752 mas, it is believed to lie approximately 3,700 light-years from Earth. The variable star NU Aquilae has a similar-looking designation but is a separate and unrelated object.

<span class="mw-page-title-main">Phi Aquilae</span> Binary star system in the constellation Aquila

Phi Aquilae, Latinized from φ Aquilae, is the Bayer designation of a binary star system in the equatorial constellation of Aquila. It has an apparent visual magnitude of +5.28 and is visible to the naked eye. With an annual parallax shift of 14.198 mas, this star is located at a distance of approximately 230 light-years from Earth. It is drifting closer with a radial velocity of –27 km/s. Based on its motion through space, this system is considered a possible member of the nearby Argus association of co-moving stars, although it may be too old.

<span class="mw-page-title-main">Upsilon Aquilae</span> Star in the constellation Aquila

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 it is a faint star but visible to the naked eye from suburban skies. It has an annual parallax shift of 18.66 mas, indicating a distance of around 175 light-years. The star is drifting closer with a radial velocity of –30 km/s.

<span class="mw-page-title-main">Psi Aquilae</span> Star in the constellation Aquila

Psi Aquilae, Latinized as ψ Aquilae, is the Bayer designation for a star in the equatorial constellation of Aquila. It is a faint star with an apparent visual magnitude of 6.25, which, according to the Bortle Dark-Sky Scale, can be seen with the naked eye in dark rural skies. The orbit of the Earth causes an annual parallax shift of 2.83 mas, which indicates a distance of approximately 1,150 light-years.

70 Aquilae, abbreviated 70 Aql, is a single orange-hued star in the equatorial constellation of Aquila. 70 Aquilae is its Flamsteed designation. It is visible to the naked eye with an apparent visual magnitude of 4.90. The distance to 70 Aquilae, as determined from its annual parallax shift of 3.5 mas, is around 940 light years. The star is moving closer to the Earth with a heliocentric radial velocity of −9 km/s.

4 Aquilae, abbreviated 4 Aql, is a single, white-hued star in the equatorial constellation of Aquila. 4 Aquilae is the Flamsteed designation. It has an apparent visual magnitude of 5.02, making it a faint star visible to the naked eye. The distance to 4 Aql can be estimated from its annual parallax shift of 6.7 mas, yielding an estimated range of around 480 light years. It is moving closer to the Earth with a heliocentric radial velocity of −13 km/s.

<span class="mw-page-title-main">20 Aquilae</span> Star in the constellation Aquila

20 Aquilae, abbreviated 20 Aql, is an irregular variable star in the equatorial constellation of Aquila. 20 Aquilae is its Flamsteed designation. It ranges in magnitude from a peak of 5.33 down to 5.36, which is bright enough for the star to be visible to the naked eye. The estimated distance to this star is around 920 light years, based upon an annual parallax shift of 3.5 mas. The star is moving closer to the Earth with a heliocentric radial velocity of −23 km/s.

14 Aquilae is a probable spectroscopic binary star system in the equatorial constellation of Aquila. 14 Aquilae is the Flamsteed designation though it also bears the Bayer designation g Aquilae. It is visible to the naked eye as a dim, white-hued star with an apparent visual magnitude of 5.42, and it is located at a distance of approximately 500 light-years from Sun. The star is moving closer to the Earth with a heliocentric radial velocity of −39 km/s, and may come as close as 136 light-years in around 3.5 million years.

<span class="mw-page-title-main">28 Aquilae</span> Star in the constellation Aquila

28 Aquilae, abbreviated 28 Aql, is a star in the equatorial constellation of Aquila. 28 Aquilae is its Flamsteed designation though it also bears the Bayer designation A Aquilae, and the variable star designation V1208 Aquilae. It has an apparent visual magnitude is 5.5, making this a faint star that requires dark suburban skies to view. The annual parallax shift of 9.6 mas means this star is located at a distance of approximately 340 light-years from Earth.

22 Aquilae, abbreviated 22 Aql, is a star in the equatorial constellation of Aquila. 22 Aquilae is its Flamsteed designation. It is a faint star but visible to the naked eye with an apparent visual magnitude of 5.59. The distance to 22 Aql can be estimated from its annual parallax shift of 4.74 mas, which yields a separation of 690 light years. It is moving closer to the Earth with a heliocentric radial velocity of −23 km/s.

58 Aquilae is a single star located around 520 light years from the Sun in the equatorial constellation of Aquila, near Eta Aquilae. 58 Aquilae is its Flamsteed designation. It is visible to the naked eye as a dim, blue-white hued star with an apparent visual magnitude of 5.60. This object is moving closer to the Earth with a heliocentric radial velocity of −53 km/s, and may come as close as 161 light-years in around 1.8 million years.

8 Aquilae is a star in the equatorial constellation of Aquila, located 271 light years away from the Sun. 8 Aquilae is the Flamsteed designation. It can be viewed with the naked eye in good seeing conditions, appearing as a dim, yellow-white hued star with an apparent visual magnitude of 6.08. The star is moving further from the Earth with a heliocentric radial velocity of +12 km/s.

<span class="mw-page-title-main">R Aquilae</span> Red giant star in the constellation Aquila

R Aquilae is a variable star in the equatorial constellation of Aquila. It is located approximately 760 light years distant from the Sun and is drifting further away with a radial velocity of 35 km/s. This is a thermally-pulsating Mira variable that ranges in brightness from 5.3 down to 12.0 with a period of 269.84 days. The period was over 300 days when first observed, and has declined steadily since – decreasing from 320 in 1915 down to 264 in 2010, at an average rate of 0.4 days per year. The amplitude of the variation has also decreased by about a magnitude since discovery. The peak magnitude is bright enough for the star to be visible to the naked eye as a dim, red-hued star.

<span class="mw-page-title-main">FF Aquilae</span> Star and possible star system in the constellation Aquila

FF Aquilae is a classical Cepheid variable star located in the constellation Aquila, close to the border with Hercules. It ranges from apparent magnitude 5.18 to 5.51 over a period of 4.47 days, meaning it is faintly visible to the unaided eye in rural or suburban settings.

45 Aquilae, abbreviated 45 Aql, is a triple star system in the equatorial constellation of Aquila. 45 Aquilae is its Flamsteed designation. It is located 350 light-years away from Earth, give or take a 6 light-year margin of error, and has a combined apparent visual magnitude of 5.7. The system is moving closer to the Earth with a heliocentric radial velocity of -46 km/s.

<span class="mw-page-title-main">V923 Aquilae</span> Binary star system in the constellation Aquila

V923 Aquilae is a variable binary star system in the equatorial constellation of Aquila. It has the designation HD 183656 from the Henry Draper Catalogue; V932 Aql is the variable star designation. The system is dimly visible to the naked eye with an apparent visual magnitude that fluctuates around 6.06. It is located at a distance of approximately 890 light years from the Sun based on parallax, but is drifting closer with a radial velocity of around −26 km/s.

Omega<sup>1</sup> Aquilae Star in the constellation Aquila

Omega1 Aquilae, which is Latinized from ω1 Aquilae, is the Bayer designation for a single star in the equatorial constellation of Aquila. With an apparent visual magnitude of 5.2 it is a faint, yellow-white hued star that can be seen with the naked eye in dark skies. From the annual parallax shift of 8.53 mas, the distance to this star can be estimated as 382 light-years, give or take a 6 light year margin of error. It is drifting closer to the Sun with a radial velocity of −14 km/s.

Omega<sup>2</sup> Aquilae Star in the constellation Aquila

Omega2 Aquilae, Latinized from ω2 Aquilae, is the Bayer designation for a star in the equatorial constellation of Aquila, the eagle. It has an apparent visual magnitude of 6.0, which is close to the lower limit of detectability with the naked eye. According to the Bortle Dark-Sky Scale, this star can be viewed from dark rural skies. As the Earth orbits about the Sun, this star undergoes a parallax shift of 11.7 mas. This is equivalent to a physical distance of 279 light-years from Earth, give or take a 2 light year margin of error. The star is drifting closer to the Sun with a radial velocity of −26 km/s.

<span class="mw-page-title-main">ET Virginis</span> Evolved red giant star in the constellation Virgo

ET Virginis is a single, red-hued star in the equatorial constellation of Virgo. It can be viewed with the naked eye, having an apparent visual magnitude of 4.91. Based upon an annual parallax shift of 5.9 mas, it is located 560 light years away. It is moving further from the Earth with a heliocentric radial velocity of +18.6 km/s, having come within 177 ly of the Sun around 6.3 million years ago.

References

  1. ↑ Veto, B. (May 1980). "Ultraviolet Observations of the Silicon Star HD 179761". Information Bulletin on Variable Stars. 1778 (1): 1. Bibcode:1980IBVS.1778....1V.
  2. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  3. 1 2 3 Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID   125853869.
  4. ↑ Cowley, A. (November 1972). "Spectral classification of the bright B8 stars". Astronomical Journal. 77: 750–755. Bibcode:1972AJ.....77..750C. doi:10.1086/111348.
  5. 1 2 Stepien, K. (December 1968). "Photometric behavior of magnetic stars". Astrophysical Journal. 154: 945. Bibcode:1968ApJ...154..945S. doi:10.1086/149815.
  6. 1 2 Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick (eds.). Proceedings from IAU Symposium no. 30. Determination of Radial Velocities and Their Applications. Vol. 30. University of Toronto: International Astronomical Union. p. 57. Bibcode:1967IAUS...30...57E.
  7. ↑ 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. S2CID   119257644.
  8. 1 2 3 4 Fouesneau, M.; Andrae, R.; Dharmawardena, T.; Rybizki, J.; Bailer-Jones, C. A. L.; Demleitner, M. (2022). "Astrophysical parameters from Gaia DR2, 2MASS, and AllWISE". Astronomy and Astrophysics. 662: A125. arXiv: 2201.03252 . Bibcode:2022A&A...662A.125F. doi:10.1051/0004-6361/202141828. S2CID   245837778.
  9. ↑ Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (20 December 2021). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics. 657: A7. arXiv: 2109.10912 . Bibcode:2022A&A...657A...7K. doi: 10.1051/0004-6361/202142146 . eISSN   1432-0746. ISSN   0004-6361.
  10. 1 2 3 Ghazaryan, S.; et al. (November 2018). "New catalogue of chemically peculiar stars, and statistical analysis". Monthly Notices of the Royal Astronomical Society. 480 (3): 2953–2962. arXiv: 1807.06902 . Bibcode:2018MNRAS.480.2953G. doi: 10.1093/mnras/sty1912 . S2CID   119062018.
  11. ↑ Oelkers, Ryan J.; Rodriguez, Joseph E.; Stassun, Keivan G.; Pepper, Joshua; Somers, Garrett; Kafka, Stella; Stevens, Daniel J.; Beatty, Thomas G.; Siverd, Robert J.; Lund, Michael B.; Kuhn, Rudolf B.; James, David; Gaudi, B. Scott (2018). "Variability Properties of Four Million Sources in the TESS Input Catalog Observed with the Kilodegree Extremely Little Telescope Survey". The Astronomical Journal. 155 (1): 39. arXiv: 1711.03608 . Bibcode:2018AJ....155...39O. doi: 10.3847/1538-3881/aa9bf4 . S2CID   119515775.
  12. ↑ Gontcharov, G. A. (December 2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters. 38 (12): 771–782. arXiv: 1606.08814 . Bibcode:2012AstL...38..771G. doi:10.1134/S1063773712120031. ISSN   0320-0108. S2CID   118345778.
  13. ↑ "21 Aql". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2019-06-05.
  14. ↑ 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 . S2CID   14878976.
  15. ↑ Renson, P.; Manfroid, J. (May 2009). "Catalogue of Ap, HgMn and Am stars". Astronomy and Astrophysics. 498 (3): 961–966. Bibcode:2009A&A...498..961R. doi: 10.1051/0004-6361/200810788 .
  16. ↑ "The Colour of Stars". Australia Telescope, Outreach and Education. Commonwealth Scientific and Industrial Research Organisation. December 21, 2004. Archived from the original on March 18, 2012. Retrieved 2012-01-16.
  17. ↑ Mason, B. D.; et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi: 10.1086/323920 . Retrieved 2015-07-22.
  18. ↑ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
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