V1401 Aquilae

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V1401 Aquilae
V1401AqlLightCurve.png
The visual band light curve of V1401 Aquilae, adapted from Waelkens & Burnet(1985) [1]
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Aquila
Right ascension 20h 05m 05.41344s [2]
Declination −11° 35 57.8964 [2]
Apparent magnitude  (V)6.38 [3] (6.18 to 6.55) [4]
Characteristics
Spectral type F2II [5]
B−V color index 0.543±0.023 [3]
Variable type SRd [4]
Astrometry
Radial velocity (Rv)−12.1±2.9 [3]  km/s
Proper motion (μ)RA: −2.585 [2]   mas/yr
Dec.: +15.629 [2]   mas/yr
Parallax (π)1.3722 ± 0.0441 [2]   mas
Distance 2,380 ± 80  ly
(730 ± 20  pc)
Details
Mass 4.1 [6]   M
Radius 35 [2]   R
Luminosity 656 [7]
1,309 [2]   L
Surface gravity (log g)1.49±0.14 [8]   cgs
Temperature 6,192±90 [8]   K
Metallicity [Fe/H]−1.12±0.08 [8]   dex
Other designations
V1401 Aql, BD−12°5641, HD  190390, HIP  98910, HR  7671, SAO  163245, WDS J20051-1136A [9]
Database references
SIMBAD data

V1401 Aquilae is a single, [10] 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. [11] 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. [3] Based on parallax measurements, it is located at a distance of approximately 2,380  light years. [2] It lies 21.5° from the galactic plane. [12]

The variability of this star was announced by W. Strohmeier and associates in 1965. [13] C. Waelkens and M. Burnet in 1985 found an irregular photometric variation with a period of around a month and suggested it is a candidate UU Herculis variable. [14] J. D. Fernie in 1986 confirmed the variability and tentatively identified periods of 28.4 and 11.8 days. He found a very low gravity with shell-like features, suggesting potential mass loss. [15] An analysis of the chemical composition by R. E. Luck and associates in 1990 found a mild enhancement of s-process elements as well as lithium, indicating it may have evolved from a lithium-rich giant. [16]

The stellar classification of V1401 Aql is F2II, [5] matching an F-type bright giant. There is strong evidence that this star belongs to the population II cepheids, and it may be a W Virginis variable. [7] On the Hertzsprung–Russell diagram it lies on the blue (hot) side of the Cepheid instability strip for population II stars. [10] Membership in the UU Herculis variable class seems less likely since it has a relatively normal radial velocity and no infrared excess has been detected. [7] The pulsation period of 28.6 days has been confirmed, but the pulsational behavior of this star is complex and it is not successfully modeled using a simple harmonic radial pulsation. [10]

The star is strongly metal deficient by a factor of 40, meaning the abundances of higher mass elements is much lower than in the Sun. There is a mild enhancement of s-process elements, although this is not considered to be intrinsic. Some investigators have suspected the star to be in an evolutionary stage following the asymptotic giant branch, but this is not confirmed based on chemical abundances. [7]

Related Research Articles

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89 Herculis Star in the constellation Hercules

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R Scuti Variable star in the constellation Scutum

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104 Herculis Star in the constellation Hercules


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R Muscae Variable star in the constellation Musca

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T Vulpeculae Variable star in the constellation Vulpecula

T Vulpeculae is a possible binary star system in the northern constellation of Vulpecula, near the star Zeta Cygni, close to the pair 31 Vulpeculae and 32 Vulpeculae. It is visible to the naked eye with an apparent visual magnitude that ranges around 5.75. The distance to this system is around 1,900 light years, as determined from its annual parallax shift of 1.67 mas.

R Crucis Variable star in the constellation Crux

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AC Herculis Star in the constellation Hercules

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W Aquilae Variable star in the constellation Aquila

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S Cassiopeiae Star in the constellation Cassiopeia

S Cassiopeiae is a Mira variable and S-type star in the constellation Cassiopeia. It is an unusually cool star, rapidly losing mass and surrounded by dense gas and dust producing masers.

SX Centauri Star in the constellation Centaurus

SX Centauri is a variable star in the constellation Centaurus. An RV Tauri variable, its light curve alternates between deep and shallow minima, varying its apparent magnitude from 9.1 to 12.4. From the period-luminosity relationship, it is estimated to be around 1.6 kpc from Earth. Gaia Data Release 2 gives a parallax of 0.2175 mas, corresponding to distance of about 4,600 pc.

HR 3831, also known as HD 83368, is a binary star system in the southern constellation of Vela at a distance of 233 light years. This object is barely visible to the naked eye as a dim, blue star with an apparent visual magnitude of 6.232. It is approaching the Earth with a heliocentric radial velocity of 4.0±0.3 km/s.

References

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  2. 1 2 3 4 5 6 7 8 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.
  3. 1 2 3 4 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.
  4. 1 2 Samus', N. N; et al. (2017). "General catalogue of variable stars". Astronomy Reports. GCVS 5.1. 61 (1): 80. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID   125853869.
  5. 1 2 Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
  6. Anders, F.; Khalatyan, A.; Chiappini, C.; Queiroz, A. B.; Santiago, B. X.; Jordi, C.; Girardi, L.; Brown, A. G. A.; Matijevič, G.; Monari, G.; Cantat-Gaudin, T.; Weiler, M.; Khan, S.; Miglio, A.; Carrillo, I.; Romero-Gómez, M.; Minchev, I.; De Jong, R. S.; Antoja, T.; Ramos, P.; Steinmetz, M.; Enke, H. (2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy and Astrophysics. 628: A94. arXiv: 1904.11302 . Bibcode:2019A&A...628A..94A. doi:10.1051/0004-6361/201935765. S2CID   131780028.
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  8. 1 2 3 Arentsen, Anke; et al. (July 2019). "Stellar atmospheric parameters for 754 spectra from the X-shooter Spectral Library". Astronomy & Astrophysics. 627: 14. arXiv: 1907.06391 . Bibcode:2019A&A...627A.138A. doi:10.1051/0004-6361/201834273. S2CID   196621431. A138.
  9. "V1401 Aql". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2021-02-23.
  10. 1 2 3 van Winckel, H.; et al. (October 2009). "Post-AGB stars with hot circumstellar dust: binarity of the low-amplitude pulsators". Astronomy and Astrophysics. 505 (3): 1221–1232. arXiv: 0906.4482 . Bibcode:2009A&A...505.1221V. doi:10.1051/0004-6361/200912332. S2CID   119299698.
  11. Wagman, M. (August 1987). "Flamsteed's Missing Stars". Journal for the History of Astronomy. 18 (3): 209–223. Bibcode:1987JHA....18..209W. doi:10.1177/002182868701800305. S2CID   118445625.
  12. Trams, N. R.; et al. (1991). "Post AGB candidates-Selection and IR properties". Astronomy and Astrophysics Supplement Series. 87: 361–382. Bibcode:1991A&AS...87..361T.
  13. Strohmeier, W.; et al. (February 1965). "Bright Southern BV-Stars". Information Bulletin on Variable Stars. 81: 1. Bibcode:1965IBVS...81....1S.
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  15. Fernie, J. D. (February 1986). "HR 7671: Another UU Herculis Star?". Astrophysical Journal. 301: 302. Bibcode:1986ApJ...301..302F. doi:10.1086/163899.
  16. Luck, R. Earle; et al. (July 1990). "Chemical Compositions of Four High-Latitude A--F Supergiants". Astrophysical Journal. 357: 188. Bibcode:1990ApJ...357..188L. doi:10.1086/168904.