38 Aquarii is a star in the equatorial constellation of Aquarius. 38 Aquarii is its Flamsteed designation; its Bayer designation is e Aquarii. It is a faint star but visible to the naked eye, with an apparent visual magnitude of +5.43.[2] Based on parallax measurements, it is around 450 light-years (140 parsecs) away;[1] it is 0.28 degree south of the ecliptic.

38 Aquarii
Diagram showing star positions and boundaries of the Aquarius constellation and its surroundings
Location of 38 Aquarii (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Aquarius
Right ascension 22h 10m 37.48206s[1]
Declination –11° 33′ 53.7754″[1]
Apparent magnitude (V) +5.43[2]
Characteristics
Spectral type B5 III[3]
B−V color index –0.12[4]
Astrometry
Radial velocity (Rv)+1.5[2] km/s
Proper motion (μ) RA: +29.29[1] mas/yr
Dec.: +8.76[1] mas/yr
Parallax (π)7.25 ± 0.33 mas[1]
Distance450 ± 20 ly
(138 ± 6 pc)
Absolute magnitude (MV)−0.26[5]
Details
Radius5.6[6] R
Luminosity219.16[5] L
Surface gravity (log g)4.00[3] cgs
Temperature13,860[3] K
Metallicity [Fe/H]–0.26[3] dex
Rotational velocity (v sin i)20[7] km/s
Other designations
38 Aqr, BD–12°6196, FK5 3771, HD 210424, HIP 109472, HR 8452, SAO 164910[8]
Database references
SIMBADdata

The spectrum of 38 Aquarii matches a stellar classification of B5 III.[3] A luminosity class of III indicates that this is an evolved giant star. It has 5.6[6] times the radius of the Sun and is spinning with a projected rotational velocity of 20 km/s.[7] The outer atmosphere of the star has a blue-white glow from an effective temperature of 13,860 K.[3]

References

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  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, S2CID 18759600.
  2. ^ a b c Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode:1999VeARI..35....1W.
  3. ^ a b c d e f Cenarro, A. J.; et al. (January 2007), "Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters", Monthly Notices of the Royal Astronomical Society, 374 (2): 664–690, arXiv:astro-ph/0611618, Bibcode:2007MNRAS.374..664C, doi:10.1111/j.1365-2966.2006.11196.x, S2CID 119428437.
  4. ^ Corben, P. M.; Stoy, R. H. (1968), "Photoelectric Magnitudes and Colours for Bright Southern Stars", Monthly Notes of the Astronomical Society of Southern Africa, 27: 11, Bibcode:1968MNSSA..27...11C.
  5. ^ a b 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.
  6. ^ 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/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
  7. ^ a b Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590.
  8. ^ "* e Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2013-05-06.