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 (γ Ceti, abbreviated Gamma Cet, γ Cet) is a triple star system in the equatorial constellation of Cetus. It has a combined apparent visual magnitude of 3.47.[1] Based upon parallax measurements, this star is located at a distance of about 80 light-years (24.4 parsecs) from the Sun.[2]

The three components are designated Gamma Ceti A (officially named Kaffaljidhma Template:IPAc-en, the traditional name for the entire system),[3] 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).[4] 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').[5] 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).[6] The IAU Working Group on Star Names (WGSN)[7] approved the name Kaffaljidhma for the component Gamma Ceti A on February 1, 2017.[3]

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').[8]

Triple system

Gamma Ceti appears to be a triple star system.[9] 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.[10] 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.[11]

At a wide separation of 840 arcseconds is component C, a dim, magnitude 10.2 K-type star with the designation Template:Nowrap.[10] It shares a common proper motion with A and is at a very similar distance,[12][9] but is separated from the close pair by over Template:Val.[13] It has a spectral classification of K5V.[14] 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.

Properties

The measured angular diameter of the primary star is Template:Nowrap.[15] At the estimated distance of this system, this yields a physical size of about 1.9 times the radius of the Sun.[16] The secondary component of this system is an X-ray source with a luminosity of Template:Nowrap.[17] Gamma Ceti is about 300 million years old,[18] and it appears to be a member of the stream of stars loosely associated with the Ursa Major Moving Group.[19] The primary has been examined for an excess of infrared emission that would suggest the presence of circumstellar matter, but none was found.[18]

References

Template:Reflist

Template:Stars of Cetus

  1. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Johnson
  2. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Leeuwen
  3. ↑ 3.0 3.1 Template:Cite web
  4. ↑ Template:Cite arXiv
  5. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named allen
  6. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named rhoads1971
  7. ↑ Template:Cite web
  8. ↑ Template:Cite web
  9. ↑ 9.0 9.1 Template:Cite web
  10. ↑ 10.0 10.1 Cite error: Invalid <ref> tag; no text was provided for refs named Eggleton
  11. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named mollise2006
  12. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named dr2c
  13. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named dhital
  14. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named stephenson
  15. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named CHARM2
  16. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named lang2006
  17. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named X-rayEmission
  18. ↑ 18.0 18.1 Cite error: Invalid <ref> tag; no text was provided for refs named DebrisDisk
  19. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named King2003
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