Astronomy:Theta Ceti

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Short description: Orange-hued giant star in the constellation Cetus
Theta Ceti
Observation data
Equinox J2000.0]] (ICRS)
Constellation Cetus
Right ascension  01h 24m 01.40328s[1]
Declination −08° 10′ 59.7392″[1]
Apparent magnitude (V) 3.60[2]
Characteristics
Evolutionary stage red clump[3]
Spectral type K0 III[4]
B−V color index +1.07[2]
Astrometry
Radial velocity (Rv)+17.2±0.5[5] km/s
Proper motion (μ) RA: −76.226[1] mas/yr
Dec.: −201.519[1] mas/yr
Parallax (π)29.0339 ± 0.2198[1] mas
Distance112.3 ± 0.9 ly
(34.4 ± 0.3 pc)
Absolute magnitude (MV)+0.89[6]
Details
Mass1.80[7] M☉
Radius10.37±0.09[8] R☉
Luminosity58.3±3.0[8] L☉
Surface gravity (log g)2.70[2] cgs
Temperature4,951±64[8] K
Metallicity [Fe/H]−0.13±0.15[2] dex
Rotational velocity (v sin i)2.60[2] km/s
Age2.20[7] Gyr
Other designations
θ Cet, 45 Cet, BD+08°244, FK5 47, HD 8512, HIP 6537, HR 402, SAO 129274[9]
Database references
SIMBADdata

Theta Ceti, Latinized from θ Ceti, is a solitary,[10] orange-hued star in the equatorial constellation of Cetus. It is visible to the naked eye with an apparent visual magnitude of 3.60.[2] Based upon an annual parallax shift of 20.04 mas as seen from Earth,[1] 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.[8]

With an age of about 2.2 billion years,[7] this is an evolved, K-type giant star with a stellar classification of K0 III.[4] It is a red clump[3] star on the horizontal branch,[2] which means it is generating energy through helium fusion at its core.[3] The star has an estimated 1.8[7] 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.[8]

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.[11] 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.[12][13]

In Chinese, 天倉 (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.[14] Consequently, the Chinese name for θ Ceti itself is 天倉三 (Tiān Cāng sān, English: the Third Star of Square Celestial Granary).[15]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Jones, M. I. et al. (December 2011), "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", Astronomy & Astrophysics 536: 7, doi:10.1051/0004-6361/201117887, A71, Bibcode: 2011A&A...536A..71J. 
  3. ↑ 3.0 3.1 3.2 Laney, C. D. et al. (January 2012), "A new Large Magellanic Cloud K-band distance from precision measurements of nearby red clump stars", Monthly Notices of the Royal Astronomical Society 419 (2): 1637–1641, doi:10.1111/j.1365-2966.2011.19826.x, Bibcode: 2012MNRAS.419.1637L. 
  4. ↑ 4.0 4.1 Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey (Ann Arbor, Michigan: Department of Astronomy, University of Michigan) 5, Bibcode: 1999MSS...C05....0H. 
  5. ↑ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics 546: 14, doi:10.1051/0004-6361/201219219, A61, Bibcode: 2012A&A...546A..61D. 
  6. ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A. 
  7. ↑ 7.0 7.1 7.2 7.3 Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal 150 (3): 88, doi:10.1088/0004-6256/150/3/88, Bibcode: 2015AJ....150...88L. 
  8. ↑ 8.0 8.1 8.2 8.3 8.4 Baines, Ellyn K.; Armstrong, J. Thomas; Schmitt, Henrique R.; Zavala, R. T.; Benson, James A.; Hutter, Donald J.; Tycner, Christopher; Van Belle, Gerard T. (2018), "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer", The Astronomical Journal 155 (1): 30, doi:10.3847/1538-3881/aa9d8b, Bibcode: 2018AJ....155...30B. 
  9. ↑ "tet Cet -- Horizontal Branch Star", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=tet+Cet, retrieved 2017-04-25. 
  10. ↑ 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E. 
  11. ↑ Knobel, E. B. (June 1895), "Al Achsasi Al Mouakket, on a catalogue of stars in the Calendarium of Mohammad Al Achsasi Al Mouakket", Monthly Notices of the Royal Astronomical Society 55: 429, doi:10.1093/mnras/55.8.429, Bibcode: 1895MNRAS..55..429K. 
  12. ↑ Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York: Dover Publications Inc, p. 162, ISBN 0-486-21079-0, https://archive.org/details/starnamestheirlo00alle/page/162, retrieved 2017-04-26. 
  13. ↑ 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.
  14. ↑ (in Chinese) 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.
  15. ↑ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 10 日



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