56 Aquarii, abbreviated 56 Aqr, is a star in the constellation of Aquarius. 56 Aquarii is its Flamsteed designation. It is a sixth magnitude star, having an apparent visual magnitude of 6.36,[2] and thus is a challenge to view with the naked eye. Based upon an annual parallax shift of 5.07 mas,[1] it is located around 643 light years from the Earth. At that distance, the visual magnitude is diminished by an extinction of 0.12 due to interstellar dust.[7] The star is moving closer with a heliocentric radial velocity of −28 km/s.[5] It is a candidate runaway star showing a transverse peculiar velocity of 213.87 km/s.[9]

Houk and Smith-Moore (1978) gave this star a stellar classification of B8 II,[4] matching a B-type bright giant. In contrast, Cowley et al. (1969) found a class of B8 Vs,[10] corresponding to a B-type main-sequence star with narrow ("sharp") absorption lines due to a relatively low projected rotation. Zorec and Royer (2012) modeled it as a dwarf star that is 67% of the way through its main sequence lifespan. It is a chemically peculiar mercury-manganese star, showing abnormally strong absorption lines of mercury and magnesium with weak lines of helium.[11] The star has 3.4[3] times the mass of the Sun and about 2.8[6] times the Sun's radius. It is radiating 185[3] times the Sun's luminosity from its photosphere at an effective temperature of 11,912 K.[3]

References

  1. ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051.
  2. ^ a b c d 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.
  3. ^ a b c d e f g h Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
  4. ^ a b Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
  5. ^ a b Gontcharov, G. A. (2006), "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, ISSN 1063-7737, S2CID 119231169.
  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 Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters, 38 (11): 694–706, arXiv:1606.09028, Bibcode:2012AstL...38..694G, doi:10.1134/S1063773712110035, S2CID 119108982.
  8. ^ "56 Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 24, 2018.
  9. ^ Mdzinarishvili, T. G.; Chargeishvili, K. B. (February 2005), "New runaway OB stars with HIPPARCOS", Astronomy and Astrophysics, 431 (2): L1 – L4, Bibcode:2005A&A...431L...1M, doi:10.1051/0004-6361:200400134.
  10. ^ Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819.
  11. ^ Saffe, C.; et al. (October 2011), "Upper Main Sequence Stars with Anomalous Abundances. The HgMn stars HR 3273, HR 8118 HR 8567 and HR 8937", Revista Mexicana de Astronomía y Astrofísica, 47: 219–234, Bibcode:2011RMxAA..47..219S.
Allikas: https://en.wikipedia.org/wiki/56_Aquarii
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