42 Capricorni is a binary star[11] system in the zodiac constellation of Capricornus. It has a combined apparent visual magnitude of 5.18,[3] so it is faintly visible to the naked eye. Its annual parallax shift of 30.09 mas yields a distance estimate of about 108 light years; the system is moving closer to the Sun with a radial velocity of −1.2 km/s.[6] 42 Capricorni is 0.2 degree south of the ecliptic and so is subject to lunar occultations.[12]

In 1995 Gregory W. Henry et al. announced that 42 Capricorni is a variable star, a discovery that was made during a survey of chromospherically active late-type stars using an automated telescope.[13] It was given its variable star designation, BY Capricorni, in the year 2000.[14] The star is an RS Canum Venaticorum variable, indicating the presence of an active chromosphere with star spots.[5]

This is a double-lined close spectroscopic binary with an orbital period of 13.174 days and an eccentricity of 0.18.[8] The binary nature of this system was discovered in 1918 by the English astronomer Joseph Lunt. It has a combined spectrum that matches a stellar classification of G1 IV,[4] with the individual components having estimated classes of G1 V and G2 V. The system is a source of X-ray emission.[15]

References

  1. ^ Henry, Gregory W.; Fekel, Francis C.; Hall, Douglas S. (December 1995). "An Automated Search for Variability in Chromospherically Active Stars". Astronomical Journal. 110: 2926–2967. Bibcode:1995AJ....110.2926H. doi:10.1086/117740. Retrieved 18 November 2021.
  2. ^ a b c d e 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.
  3. ^ a b c d Ducati, J. R. (2002), "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system", CDS/ADC Collection of Electronic Catalogues, 2237, Bibcode:2002yCat.2237....0D.
  4. ^ a b c d e Gray, R. O.; et al. (2006), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc--The Southern Sample", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637, S2CID 119476992.
  5. ^ a b c d e f g Fekel, Francis C. (December 1997), "Chromospherically active stars. XVI. The double-lined binary 42 Capricorni", Astronomical Journal, 114: 2747, Bibcode:1997AJ....114.2747F, doi:10.1086/118683
  6. ^ a b Karataș, Yüksel; Bilir, Selçuk; Eker, Zeki; Demircan, Osman; Liebert, James; Hawley, Suzanne L.; Fraser, Oliver J.; Covey, Kevin R.; Lowrance, Patrick; Kirkpatrick, J. Davy; Burgasser, Adam J. (2004). "Kinematics of chromospherically active binaries and evidence of an orbital period decrease in binary evolution". Monthly Notices of the Royal Astronomical Society. 349 (3): 1069–1092. arXiv:astro-ph/0404219. Bibcode:2004MNRAS.349.1069K. doi:10.1111/j.1365-2966.2004.07588.x. S2CID 15290475.
  7. ^ Ammler-von Eiff, Matthias; Reiners, Ansgar (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics, 542: A116, arXiv:1204.2459, Bibcode:2012A&A...542A.116A, doi:10.1051/0004-6361/201118724, S2CID 53666672.
  8. ^ a b Pourbaix, D.; et al. (2004), "SB9: The Ninth Catalogue of Spectroscopic Binary Orbits", Astronomy & Astrophysics, 424: 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213, S2CID 119387088.
  9. ^ a b Chen, Y. Q.; et al. (February 2000), "Chemical composition of 90 F and G disk dwarfs", Astronomy and Astrophysics Supplement, 141 (3): 491–506, arXiv:astro-ph/9912342, Bibcode:2000A&AS..141..491C, doi:10.1051/aas:2000124, S2CID 16273589.
  10. ^ "42 Cap". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-01-27.
  11. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
  12. ^ Herr, Richard B. (April 1969), "Identification List of Spectroscopic and Eclipsing Binaries Subject to Occultations by the Moon", Publications of the Astronomical Society of the Pacific, 81 (479): 105, Bibcode:1969PASP...81..105H, doi:10.1086/128748.
  13. ^ Henry, Gregory W.; Fekel, Francis C.; Hall, Douglas S. (December 1995). "An Automated Search for Variability in Chromospherically Active Stars". Astronomical Journal. 110: 2926–2967. Bibcode:1995AJ....110.2926H. doi:10.1086/117740. Retrieved 7 January 2025.
  14. ^ Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V. (March 2000). "The 75th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 4870: 1–47. Bibcode:2000IBVS.4870....1K. Retrieved 7 January 2025.
  15. ^ Haakonsen, Christian Bernt; Rutledge, Robert E. (September 2009), "XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources", The Astrophysical Journal Supplement, 184 (1): 138–151, arXiv:0910.3229, Bibcode:2009ApJS..184..138H, doi:10.1088/0067-0049/184/1/138, S2CID 119267456.
Allikas: https://en.wikipedia.org/wiki/42_Capricorni
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