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]

In 1962, Helmut A. Abt and John C. Gloson published data showing that 21 Aquilae was a variable star. [15] Based on that publication, the star was given its variable star designation in 1972. [16]

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. [17] 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. [18]

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. [19] The companion is a distant background object. [20]

Related Research Articles

<span class="mw-page-title-main">V1494 Aquilae</span> Nova seen in 1999 in the constellation of Aquila

V1494 Aquilae or Nova Aquilae 1999 b was a nova which occurred during 1999 in the constellation Aquila and reached a brightness of magnitude 3.9 on 2 December 1999. making it easily visible to the naked eye. The nova was discovered with 14×100 binoculars by Alfredo Pereira of Cabo da Roca, Portugal at 18:50 UT on 1 December 1999, when it had a visual magnitude of 6.0.

<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">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.

11 Aquilae is a single star in the equatorial constellation of Aquila. 11 Aquilae is the Flamsteed designation. It has an apparent visual magnitude of 5.2, which means it is faintly visible to the naked eye. Based upon an annual parallax shift of 20.9 mas, the distance to this star is approximately 156 light-years. The brightness of this star is diminished by 0.33 in magnitude because of extinction from interstellar gas and dust.

<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">10 Aquilae</span> Star in the constellation Aquila

10 Aquilae is a star in the equatorial constellation of Aquila. 10 Aquilae is the Flamsteed designation. It has an apparent visual magnitude of 5.9 and thus is a faint star that is just visible to the naked eye in dark skies. The brightness of this star is diminished by 0.17 in visual magnitude from extinction caused by interstellar gas and dust. Based on an annual parallax shift of 13.45 mas, the distance to this star is around 240 light-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 magnitude 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">V Aquilae</span> Star in the constellation Aquila

V Aquilae is a carbon star and semiregular variable star in the constellation Aquila. It has an apparent magnitude which varies between 6.6 and 8.4 and is located around 400 parsecs (1,300 ly) away.

<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.

<span class="mw-page-title-main">V1291 Aquilae</span> Variable star in the constellation Aquila

V1291 Aquilae is a single star in the equatorial constellation of Aquila. It has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude that fluctuates around 5.65. Based on parallax measurements, it is located at a distance of approximately 278 light years from the Sun. The star it is drifting closer with a radial velocity of −22 km/s.

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.

<span class="mw-page-title-main">V1401 Aquilae</span> Star in the constellation Aquila

V1401 Aquilae is a single, semi-regular pulsating star in the equatorial constellation of Aquila. It has the designation HD 190390 from the Henry Draper Catalogue, and was formerly designated 64 Sagittarii. The evolutionary status of the star is unclear, and it has been classified as a post-AGB object, a UU Herculis variable, or belonging to the W Virginis variable subclass of the type II Cepheids. It is dimly visible to the naked eye with an apparent visual magnitude that fluctuates around 6.38. Based on parallax measurements, it is located at a distance of approximately 2,380 light years. It lies 21.5° from the galactic plane.

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.

46 Aquilae is a star in the constellation of Aquila, located to the north of Tarazed. 46 Aquilae is its Flamsteed designation. It is a dim, blue-white hued star that is a challenge to view with the naked eye, having an apparent visual magnitude of 6.33. This object is located approximately 830 light years from the Sun, based on parallax. It is moving closer to the Earth with a heliocentric radial velocity of −25 km/s.

<span class="mw-page-title-main">HD 190007</span> Star in the constellation Aquila

HD 190007, also known as Gliese 775, is a star with a close orbiting exoplanet in the constellation of Aquila. Parallax measurements by Gaia put the star at a distance of 41.5 light-years away from the Sun. It is drifting closer with a radial velocity of −30.3 km/s, and is predicted to come within 11.8 light-years in 375,000 years. The star has an absolute magnitude of 6.91, but at its present distance the apparent visual magnitude is 7.46, which is too faint to be viewed with the naked eye.

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. ↑ Abt, Helmut A.; Golson, John C. (July 1962). "Colors and Variability of Magnetic Stars". Astrophysical Journal. 136: 35–51. Bibcode:1962ApJ...136...35A. doi:10.1086/147349 . Retrieved 21 November 2024.
  16. ↑ Kukarkin, B. V.; Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (September 1972). "58th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 717. Bibcode:1972IBVS..717....1K . Retrieved 21 November 2024.
  17. ↑ 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 .
  18. ↑ "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.
  19. ↑ 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.
  20. ↑ 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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