Astronomy:V Aquilae

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Short description: Star in the constellation Aquila
V Aquilae
Aquila constellation map.svg
Red circle.svg
Location of V Aquilae (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Aquila
Right ascension  19h 04m 24.155s[1]
Declination −05° 41′ 05.44″[1]
Apparent magnitude (V) 6.6 - 8.4[2]
Characteristics
Spectral type C5,4-C6,4(N6)[2]
B−V color index +4.32[3]
Variable type SRb[2]
Astrometry
Radial velocity (Rv)+37[4] km/s
Proper motion (μ) RA: 6.243±0.407[5] mas/yr
Dec.: −1.379±0.318[5] mas/yr
Parallax (π)2.4779 ± 0.2320[5] mas
Distance1,300 ± 100 ly
(400 ± 40 pc)
Absolute magnitude (MV)−5.19[6]
Details
Mass2.5[7] M☉
Radius234[8] R☉
Luminosity6,500[9] L☉
Surface gravity (log g)−0.108[8] cgs
Temperature2,800[9] K
Metallicity [Fe/H]0.10[10] dex
Other designations
BD−05 4858, HD 177336, HIP 93666, HR 7220, SAO 142985[11]
Database references
SIMBADdata

V Aquilae (V Aql) 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.

V Aquilae is a type of star with a spectrum that is dominated by strong absorption lines of the molecules C2 and CN, hence known as carbon stars. The enhanced levels of carbon in the atmosphere originate from recently nucleosynthesized material that has been dredged up to the surface by deep convection during temporary shell burning events known as thermal pulses. Published spectral types for the star vary somewhat from C54 to C64, or N6 under an older system of classification.[2][12] The subscript 4 refers to the strength of the molecular carbon bands in the spectrum, an indicator of the relatively abundances of carbon in the atmosphere.

A light curve for V Aquilae, plotted from Hipparcos data[13]

V Aquilae is a variable star of type SRb.[10] It has a published period of 400 days, but other periods are found including 350 days and 2,270 days.[14]

References

  1. ↑ 1.0 1.1 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V. http://www.aanda.org/articles/aa/full/2007/41/aa8357-07/aa8357-07.html. Vizier catalog entry
  2. ↑ 2.0 2.1 2.2 2.3 Samus, N. N. et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S 1: B/gcvs. Bibcode: 2009yCat....102025S. 
  3. ↑ Nicolet, B. (October 1978). "Catalogue of homogeneous data in the UBV photoelectric photometric system". Astronomy & Astrophysics Supplement Series 34: 1–49. Bibcode: 1978A&AS...34....1N. 
  4. ↑ Wilson, Ralph Elmer (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication: 0. Bibcode: 1953GCRV..C......0W. 
  5. ↑ 5.0 5.1 5.2 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  6. ↑ Guandalini, R; Cristallo, S (2013). "Luminosities of carbon-rich asymptotic giant branch stars in the Milky Way". Astronomy & Astrophysics 555: A120. doi:10.1051/0004-6361/201321225. Bibcode: 2013A&A...555A.120G. 
  7. ↑ Anders, F.; Khalatyan, A.; Chiappini, C.; Queiroz, A. B.; Santiago, B. X.; Jordi, C.; Girardi, L.; Brown, A. G. A. et al. (2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy and Astrophysics 628: A94. doi:10.1051/0004-6361/201935765. Bibcode: 2019A&A...628A..94A. 
  8. ↑ 8.0 8.1 McDonald, I.; Zijlstra, A. A.; Watson, R. A. (2017). "Fundamental parameters and infrared excesses of Tycho-Gaia stars". Monthly Notices of the Royal Astronomical Society 471 (1): 770. doi:10.1093/mnras/stx1433. Bibcode: 2017MNRAS.471..770M. 
  9. ↑ 9.0 9.1 Schöier, F. L; Ramstedt, S; Olofsson, H; Lindqvist, M; Bieging, J. H; Marvel, K. B (2013). "The abundance of HCN in circumstellar envelopes of AGB stars of different chemical type". Astronomy & Astrophysics 550: A78. doi:10.1051/0004-6361/201220400. Bibcode: 2013A&A...550A..78S. 
  10. ↑ 10.0 10.1 Lambert, David L.; Gustafsson, Bengt; Eriksson, Kjell; Hinkle, Kenneth H. (October 1986). "The chemical composition of carbon stars. I - Carbon, nitrogen, and oxygen in 30 cool carbon stars in the Galactic disk". Astrophysical Journal Supplement Series 62: 373–425. doi:10.1086/191145. Bibcode: 1986ApJS...62..373L. 
  11. ↑ "V* V Aql -- Semi-regular pulsating Star". Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=V+Aql. 
  12. ↑ Skiff, B. A. (2014). "VizieR Online Data Catalog: Catalogue of Stellar Spectral Classifications (Skiff, 2009-2016)". VizieR On-line Data Catalog: B/Mk. Originally Published in: Lowell Observatory (October 2014) 1: B/mk. Bibcode: 2014yCat....1.2023S. 
  13. ↑ "Hipparcos Tools Interactive Data Access". ESA. https://www.cosmos.esa.int/web/hipparcos/interactive-data-access. 
  14. ↑ Olivier, E. A; Wood, P. R (2003). "On the Origin of Long Secondary Periods in Semiregular Variables". The Astrophysical Journal 584 (2): 1035–1041. doi:10.1086/345715. Bibcode: 2003ApJ...584.1035O. 

External links



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