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56 Aquarii

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 5.01 mas, it is located around 653 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,[10] matching a B-type bright giant. In contrast, Cowley et al. (1969) found a class of B8 Vs,[4] 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 3.6 times the mass of the Sun and about 3.2 times the Sun's radius. It is radiating 230 times the Sun's luminosity from its photosphere at an effective temperature of 12,500 K.[1]

References

  1. ^ a b c d e f Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  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 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 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.
  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. ^ Ghazaryan, S.; Alecian, G.; Hakobyan, A. A. (2018-11-01), "New catalogue of chemically peculiar stars, and statistical analysis", Monthly Notices of the Royal Astronomical Society, 480 (3): 2953–2962, arXiv:1807.06902, Bibcode:2018MNRAS.480.2953G, doi:10.1093/mnras/sty1912, ISSN 0035-8711.
  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. ^ 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.
  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.