Theta Ceti
{{short description|Orange-hued giant star in the constellation Cetus}}
{{Starbox begin
| name = Theta Ceti
}}
{{Starbox observe
| epoch = J2000.0
| constell = Cetus
| dec = {{DEC|−08|10|59.7392}}
}}
{{Starbox character
| type = red clump
| u-b =
| r-i =
| variable =
}}
{{Starbox astrometry
| radial_v = {{Val|+17.2|0.5}}
| prop_mo_ra = {{val|-76.226}}
| prop_mo_dec = {{val|-201.519}}
| parallax = 29.0339
| p_error = 0.2198
}}
{{Starbox detail
| luminosity = {{val|58.3|3.0}}
| temperature = {{Val|4951|64|fmt=commas}}
| metal_fe = {{Val|−0.13|0.15}}
}}
{{Starbox catalog
| names = θ Cet, 45 Cet, BD+08°244, FK5 47, HD 8512, HIP 6537, HR 402, SAO 129274
}}
{{Starbox reference
| Simbad = tet+Cet
}}
{{Starbox end}}
Theta Ceti, Latinized from θ Ceti, is a solitary, orange-hued star in the equatorial constellation of Cetus. It is visible to the naked eye with an apparent visual magnitude of 3.60. Based upon an annual parallax shift of 20.04 mas as seen from Earth, it is located about 113 light-years from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.28 due to interstellar dust.
With an age of about 2.2 billion years, this is an evolved, K-type giant star with a stellar classification of K0 III. It is a red clump star on the horizontal branch, which means it is generating energy through helium fusion at its core. The star has an estimated 1.8 times the mass of the Sun and has expanded to 10 times the Sun's radius. It is radiating 58 times the solar luminosity from its photosphere at an effective temperature of 4,951 K.
Name
In the catalogue of stars in the Calendarium of Al Achsasi Al Mouakket, this star was designated Thanih al Naamat (ثاني النعامات - thānī al-naʽāmāt), which was translated into Latin as Secunda Struthionum, meaning the second ostrich. This star, along with η Cet (Deneb Algenubi), τ Cet (Thalath Al Naamat), ζ Cet (Baten Kaitos) and υ Cet, were Al Naʽāmāt (النعامات), the Hen Ostriches.η Cet as Aoul al Naamat or Prima Struthionum (the first ostrich), θ Cet as Thanih al Naamat or Secunda Struthionum (the second ostrich), τ Cet as Thalath al Naamat or Tertia Struthionum (the third ostrich), and ζ Cet as Rabah al Naamat or Quarta Struthionum (the fourth ostrich). υ Cet should be Khamis al Naamat or Quinta Struthionum (the fifth ostrich) consistently, but Al Achsasi Al Mouakket designated the title the fifth ostrich to γ Gam with uncleared consideration.
In Chinese, {{lang|zh|天倉}} ({{lang|zh-Latn|Tiān Cāng}}), meaning Square Celestial Granary, refers to an asterism consisting of θ Ceti, ι Ceti, η Ceti, ζ Ceti, τ Ceti and 57 Ceti.{{in lang|zh}} 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, {{ISBN|978-986-7332-25-7}}. Consequently, the Chinese name for θ Ceti itself is {{lang|zh|天倉三}} ({{lang|zh-Latn|Tiān Cāng sān}}, {{langx|en|the Third Star of Square Celestial Granary}}).{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0607/ap060710.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 10 日] {{Webarchive|url=https://web.archive.org/web/20110716123113/http://aeea.nmns.edu.tw/2006/0607/ap060710.html |date=2011-07-16 }}
References
{{reflist|refs=
{{Cite DR3|2478112158887431296}}
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| postscript=. |arxiv = 0806.2878 | s2cid=14878976 }}
| title=Study of the impact of the post-MS evolution of the host star on the orbits of close-in planets. I. Sample definition and physical properties
| last1=Jones | first1=M. I. | last2=Jenkins | first2=J. S.
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| journal=Astronomy & Astrophysics | display-authors=1
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| title=tet Cet -- Horizontal Branch Star
| work=SIMBAD Astronomical Database
| publisher=Centre de Données astronomiques de Strasbourg
| url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=tet+Cet
| access-date=2017-04-25 | postscript=. }}
| last=Knobel | first=E. B.
| title=Al Achsasi Al Mouakket, on a catalogue of stars in the Calendarium of Mohammad Al Achsasi Al Mouakket
| journal=Monthly Notices of the Royal Astronomical Society
| volume=55 | page=429 | date=June 1895 | postscript=.
| bibcode=1895MNRAS..55..429K | doi=10.1093/mnras/55.8.429| doi-access=free}}
}}
{{Stars of Cetus|state=collapsed}}
{{DEFAULTSORT:Theta Ceti}}
Category:Horizontal-branch stars