Gamma Ceti

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Template:Short description Template:Starbox begin Template:Starbox image Template:Starbox observe Template:Starbox character Template:Starbox astrometry Template:Starbox detail Template:Starbox catalog Template:Starbox reference Template:Starbox end Gamma Ceti is a triple star system in the equatorial constellation of Cetus. Its name is a Bayer designation that is Latinized from γ Ceti, and abbreviated Gamma Cet or γ Cet. This system combined apparent visual magnitude of 3.47,[1] which is bright enough to be visible to the naked eye. Based upon parallax measurements, this system is located at a distance of about 80 light-years (24.4 parsecs) from the Sun.[2] It is drifting closer to the Sun with a line of sight velocity component of –5 km/s.[3]

The three components are designated Gamma Ceti A (officially named Kaffaljidhma Template:IPAc-en, the traditional name for the entire system),[4] B and C.

Nomenclature

γ Ceti (Latinised to Gamma Ceti) is the system's Bayer designation. The designations of the three components as Gamma Ceti A, B and C derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[5] The close pair AB is also designated HIP 12706, HD 16970, and HR 804. The system of A, B, and C is collectively designated GJ 106.1 in the Gliese Catalogue of Nearby Stars.

Gamma Ceti bore the traditional names of Template:Lang or Template:Lang, derived from Template:Langx Template:Lang ('the cut-short hand').[6] According to a 1971 NASA memorandum, Template:Lang was originally the title for five stars: Gamma Ceti as Template:Lang, Xi1 Ceti as Template:Lang, Xi2 Ceti as Template:Lang, Delta Ceti as Template:Lang and Mu Ceti as Template:Lang (excluding Alpha Ceti and Lambda Ceti).[7] The IAU Working Group on Star Names (WGSN)[8] approved the name Kaffaljidhma for the component Gamma Ceti A on February 1, 2017.[4]

In Chinese astronomy, Template:Lang Template:Lang, meaning 'Circular Celestial Granary', refers to an asterism consisting of Gamma Ceti, Alpha Ceti, Kappa1 Ceti, Lambda Ceti, Mu Ceti, Xi1 Ceti, Xi2 Ceti, Nu Ceti, Delta Ceti, 75 Ceti, 70 Ceti, 63 Ceti and 66 Ceti. Consequently, the Chinese name for Gamma Ceti itself is Template:Lang Template:Lang ('the Eighth Star of Circular Celestial Granary').[9]

System

Gamma Ceti appears to be a triple star system.[10] The inner pair (A and B) have an angular separation of 2.6 arcseconds. The primary component of this pair (A) is an A-type main sequence star with a stellar classification of A3 V and a visual magnitude of 3.6. The fainter secondary component (B) is an F-type main sequence star that has a classification of F3 V and a magnitude of 6.6.[11] The contrasting colors of these two stars makes them a popular target of amateur astronomers. The two can be resolved with a small, Template:Convert aperture telescope under ideal seeing conditions, although at times they can be a challenge to resolve even with a much larger scope.[12]

At a wide separation of 840 arcseconds is component C, a dim, magnitude 10.2 K-type star with the designation Template:Nowrap.[11] It shares a common proper motion with A and is at a very similar distance,[13][10] but is separated from the close pair by over Template:Val.[14] It has a spectral classification of K5V.[15] There are several other stars brighter and closer to Gamma Ceti than Template:Nowrap – Template:Nowrap, HD 16985, and Template:Nowrap – but they are all more distant background stars.Template:Cn

Properties

The measured angular diameter of the primary star is Template:Val.[16] At the estimated distance of this system, this yields a physical size of about 1.9 times the radius of the Sun.[17] The secondary component of this system is an X-ray source with a luminosity of Template:Val.[18] Gamma Ceti is about 300 million years old,[19] and it appears to be a member of the stream of stars loosely associated with the Ursa Major Moving Group.[20] The primary has been examined for an excess of infrared emission that would suggest the presence of circumstellar matter, but none was found.[19]

References

  1. ↑ Template:Cite XHIP Cite error: <ref> tag with name "Anderson2012" defined in <references> is not used in prior text.
  2. ↑ Template:Cite journal Cite error: <ref> tag with name "Gray2003" defined in <references> is not used in prior text.
  3. ↑ Template:Cite journal Cite error: <ref> tag with name "Royer2007" defined in <references> is not used in prior text.
  4. ↑ Template:Cite simbad Cite error: <ref> tag with name "SIMBAD" defined in <references> is not used in prior text.
  5. ↑ Template:Cite journal Cite error: <ref> tag with name "gullikson" defined in <references> is not used in prior text.
  6. ↑ Template:Cite journal Cite error: <ref> tag with name "tokovinin" defined in <references> is not used in prior text.
  7. ↑ Template:Cite journal
  8. ↑ Template:Cite journal
  9. ↑ Template:Cite journal
  10. ↑ 4.0 4.1 Template:Cite web
  11. ↑ Template:Cite arXiv
  12. ↑ Template:Cite book
  13. ↑ Template:Cite report
  14. ↑ Template:Cite web
  15. ↑ Template:Cite web
  16. ↑ 10.0 10.1 Template:Cite web
  17. ↑ 11.0 11.1 Template:Cite journal
  18. ↑ Template:Cite book
  19. ↑ Template:Cite DR2
  20. ↑ Template:Cite journal
  21. ↑ Template:Cite journal
  22. ↑ Template:Cite journal
  23. ↑ Template:Cite book
    The radius (R*) is given by:
    2⋅R∗=(24.4⋅0.74⋅10−3) AU0.0046491 AU/R⨀≈3.88⋅R⨀
  24. ↑ Template:Cite journal
  25. ↑ 19.0 19.1 Template:Cite journal
  26. ↑ Template:Cite journal

Template:Stars of Cetus

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