28 Aquilae

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28 Aquilae
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila
Right ascension 19h 19m 39.34859s[1]
Declination +12° 22′ 28.8521″[1]
Apparent magnitude (V) 5.531[2]
Characteristics
Spectral type F0 III[2]
U−B color index +0.182[3]
B−V color index +0.257[3]
Variable type δ Sct[4]
Astrometry
Radial velocity (Rv) +4.36[2] km/s
Proper motion (μ) RA: 5.21[1] mas/yr
Dec.: 17.30[1] mas/yr
Parallax (π) 9.67 ± 0.32[1] mas
Distance 340 ± 10 ly
(103 ± 3 pc)
Details
Surface gravity (log g) 3.41[5] cgs
Temperature 7,250[2] K
Metallicity [Fe/H] –0.16[2] dex
Rotational velocity (v sin i) 57[6] km/s
Other designations
A Aquilae, BD+12° 3879, HD 181333, HIP 94982, HR 7331, SAO 104722.[7]

28 Aquilae is the Flamsteed designation for a star in the equatorial constellation of Aquila. It has an apparent visual magnitude is 5.5,[2] making this a faint star that requires dark suburban skies to view (according to the Bortle Dark-Sky Scale). The annual parallax shift of 9.67 mas[1] means this star is located at a distance of approximately 340 light-years (100 parsecs) from Earth.

The spectrum of this star matches a stellar classification of F0 III,[2] with the luminosity class of III indicating this is most likely an evolved giant star. The variability of this star was discovered by Michel Breger in 1969. It was revealed to be a Delta Scuti-type pulsating variable star with at least two periods of pulsation. The known periods have frequencies of 6.68 and 7.12 cycles per day.[4] The outer atmosphere has an effective temperature of 7,250 K,[2] which lies in the range of a yellow-white hued F-type star.[8]

References[edit]

  1. ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d e f g h Luck, R. Earle; Heiter, Ulrike (June 2007), "Giants in the Local Region", The Astronomical Journal 133 (6): 2464–2486, Bibcode:2007AJ....133.2464L, doi:10.1086/513194. 
  3. ^ a b Breger, M. (March 1968), "UBV and narrow-band UVBY photometry of bright stars", Astronomical Journal 73: 84–85, Bibcode:1968AJ.....73...84B, doi:10.1086/110602. 
  4. ^ a b Dall, T. H.; Frandsen, S. (May 2002), "Mode characterisation in delta Scuti stars. I. rho Pup, GN And, V1208 Aql and AV Cet", Astronomy and Astrophysics 386: 964–970, Bibcode:2002A&A...386..964D, doi:10.1051/0004-6361:20020357. 
  5. ^ Caillo, A. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics 515: A111, arXiv:1004.1069, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247. 
  6. ^ Royer, F. et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics 393: 897–911, arXiv:astro-ph/0205255, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943. 
  7. ^ "V1208 Aql -- Variable Star of delta Sct type", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), retrieved 2012-07-22. 
  8. ^ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16. 

External links[edit]