36 Aquilae

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36 Aquilae
Diagram showing star positions and boundaries of the Aquila constellation and its surroundings
Cercle rouge 100%.svg

Location of 36 Aquarii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila
Right ascension 19h 30m 39.83606s[1]
Declination –02° 47′ 19.9944″[1]
Apparent magnitude (V) 5.02[2]
Spectral type M1 III[3]
U−B color index +2.03[2]
B−V color index +1.75[2]
Radial velocity (Rv) –10.38 ± 0.55[4] km/s
Proper motion (μ) RA: +20.64[1] mas/yr
Dec.: –10.63[1] mas/yr
Parallax (π) 6.17 ± 0.30[1] mas
Distance 530 ± 30 ly
(162 ± 8 pc)
Radius 54[5] R
Other designations
BD–03° 4612, FK5 1509, HD 183630, HIP 95937, HR 7414, SAO 143482.[3]
Database references

36 Aquilae (abbreviated 36 Aql) is a star in the equatorial constellation of Aquila. 36 Aquilae is its Flamsteed designation though it also bears the Bayer designation e Aquilae. With an apparent visual magnitude of 5.02,[2] this star is faintly visible to the naked eye. It has an annual parallax shift of 6.17 mas, indicating a physical distance of 530 light-years (160 parsecs) with a 30 light-year margin of error.[1]

The spectrum of this star matches a stellar classification of M1 III.[3] It is a red giant star with 54[5] times the radius of the Sun that is currently on the asymptotic giant branch.[6] This means the star is generating energy by the fusion of hydrogen along an outer shell and helium along a concentric inner shell, surrounding an inert core of carbon and oxygen. 36 Aquilae undergoes small, periodic variations in luminosity, changing by 0.0063 magnitudes about 11.5 times per day, or once every 2 hours and 5.2 minutes.[7]


  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:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Cousins, A. W. J. (1964), "Photometric Data for Stars in the Equatorial Zone (Seventh List)", Monthly Notes of the Astronomical Society of Southern Africa, 23: 175, Bibcode:1964MNSSA..23..175C. 
  3. ^ a b c "e Aql -- Variable Star", SIMBAD Astronomical Object Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-22. 
  4. ^ Famaey, B.; et al. (May 2009), "Spectroscopic binaries among Hipparcos M giants. I. Data, orbits, and intrinsic variations", Astronomy and Astrophysics, 498 (2): 627–640, arXiv:0901.0934Freely accessible, Bibcode:2009A&A...498..627F, doi:10.1051/0004-6361/200810698. 
  5. ^ a b Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics, 367 (2): 521–524, arXiv:astro-ph/0012289Freely accessible, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451. 
  6. ^ Eggen, Olin J. (July 1992), "Asymptotic giant branch stars near the sun", Astronomical Journal, 104 (1): 275–313, Bibcode:1992AJ....104..275E, doi:10.1086/116239. 
  7. ^ Koen, Chris; Eyer, Laurent (March 2002), "New periodic variables from the Hipparcos epoch photometry", Monthly Notices of the Royal Astronomical Society, 331 (1): 45–59, arXiv:astro-ph/0112194Freely accessible, Bibcode:2002MNRAS.331...45K, doi:10.1046/j.1365-8711.2002.05150.x. 

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