38 Aquarii

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[1] mas
Distance450 ± 20 ly
(138 ± 6 pc)
Details
Radius5.6[5] R☉
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[6] km/s
Other designations
38 Aqr, e Aqr, BD–12 6196, FK5 3771, HD 210424, HIP 109472, HR 8452, SAO 164910.[7]

38 Aquarii (e Aquarii, e Aqr, 38 Aqr) is the Flamsteed designation for a star in the equatorial constellation of Aquarius. It is a faint star but visible to the naked eye, with an apparent visual magnitude of +5.43.[2] The distance to this star, based upon parallax measurements, is around 450 light-years (140 parsecs).[1]

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[5] times the radius of the Sun and is spinning with a projected rotational velocity of 20 km/s.[6] The outer atmosphere of the star has a blue-white glow from an effective temperature of 13,860 K.[3]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 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. ↑ 2.0 2.1 2.2 Wielen, R. et al. (1999), Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions (35), Astronomisches Rechen-Institut Heidelberg, Bibcode:1999VeARI..35....1W.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 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.
  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. ↑ 5.0 5.1 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.
  6. ↑ 6.0 6.1 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.
  7. ↑ "e Aqr -- Star", SIMBAD Astronomical Object Database (Centre de Données astronomiques de Strasbourg), 6 April 2013, retrieved 2013-05-06