Astronomy:38 Aquarii

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Short description: Star in the constellation Aquarius
38 Aquarii
Diagram showing star positions and boundaries of the Aquarius constellation and its surroundings
Cercle rouge 100%.svg
Location of 38 Aquarii (circled)
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
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)
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

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.

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

  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, doi:10.1051/0004-6361:20078357, Bibcode2007A&A...474..653V. 
  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", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg (Astronomisches Rechen-Institut Heidelberg) 35 (35): 1, Bibcode1999VeARI..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, doi:10.1111/j.1365-2966.2006.11196.x, Bibcode2007MNRAS.374..664C. 
  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, Bibcode1968MNSSA..27...11C. 
  5. 5.0 5.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  6. 6.0 6.1 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, doi:10.1051/0004-6361:20000451, Bibcode2001A&A...367..521P. 
  7. 7.0 7.1 Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal 573 (1): 359–365, doi:10.1086/340590, Bibcode2002ApJ...573..359A. 
  8. "* e Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+e+Aqr.