Upsilon Ceti

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Upsilon Ceti
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cetus
Right ascension 02h 00m 00.30916s[1]
Declination −21° 04′ 40.1946″[1]
Apparent magnitude (V) 3.95[2]
Spectral type K5/M0III[3]
U−B color index +1.90[2]
B−V color index +1.57[2]
Radial velocity (Rv) +18.00±0.70[4] km/s
Proper motion (μ) RA: +134.92[1] mas/yr
Dec.: −24.59[1] mas/yr
Parallax (π) 11.14 ± 0.18[1] mas
Distance 293 ± 5 ly
(90 ± 1 pc)
Mass 1.26±0.13 M
Radius 53.56±11.80 R
Luminosity 549.6±226.8 L
Surface gravity (log g) 1.15±0.18 cgs
Temperature 3,822±148 K
Metallicity [Fe/H] −0.06±0.10 dex
Age 6.97±2.77 Gyr
Other designations
υ Cet, 59 Cet, BD−21° 358, FK5 71, HD 12274, HIP 9347, HR 585, SAO 167471.[6]
Database references

Upsilon Ceti (υ Ceti, υ Cet) is a solitary[7] star in the equatorial constellation of Cetus. It is visible to the naked eye with an apparent visual magnitude of 3.95.[2] Based upon an annual parallax shift of 11.14 mas,[1] it is located about 293 light years from the Sun.

This star was designated Upsilon Ceti by Bayer and 59 Ceti by Flamsteed. Flamsteed also gave it the designation Upsilon2 Ceti to distinguish it from 56 Ceti, which he called Upsilon1. Flamsteed's superscripted designations, however, are not in general use today.[8]

For ancient Arabic astronomers, this star with η Cet (Deneb Algenubi), θ Cet (Thanih al Naamat), τ Cet (Durre Menthor) and ζ Cet (Baten Kaitos), formed Al Naʽāmāt (ألنعامة), the Hen Ostriches[9] In Chinese, 鈇鑕 (Fū Zhì), meaning Sickle, refers to an asterism consisting of υ Ceti, 48 Ceti and 56 Ceti.[10] Consequently, υ Ceti itself is known as 鈇鑕四 (Fū Zhì sì, English: the Fourth Star of Sickle.)[11]

Upsilon Ceti is a evolved red giant star with a stellar classification of K5/M0III.[3] It has an 84% chance on the red giant branch, or 16% to be on the horizontal branch. Stellar models based on the red giant branch status yield an estimated mass of around 126% of the Sun's mass and 54 times the radius of the Sun. This model indicates the star radiates around 550 times the solar luminosity from its outer atmosphere at an effective temperature of 3,822 K.[5]


  1. ^ a b c d e f van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752Freely accessible, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV data, SIMBAD, Bibcode:1986EgUBV........0M. 
  3. ^ a b Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988MSS...C04....0H. 
  4. ^ 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, Bibcode:2012A&A...546A..61D, arXiv:1208.3048Freely accessible, doi:10.1051/0004-6361/201219219, A61. 
  5. ^ a b Reffert, Sabine; et al. (2015), "Precise radial velocities of giant stars. VII. Occurrence rate of giant extrasolar planets as a function of mass and metallicity", Astronomy and Astrophysics, 574A (2): 116–129, Bibcode:2015A&A...574A.116R, arXiv:1412.4634Freely accessible, doi:10.1051/0004-6361/201322360. 
  6. ^ "ups Cet -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-02-12. 
  7. ^ 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, Bibcode:2008MNRAS.389..869E, arXiv:0806.2878Freely accessible, doi:10.1111/j.1365-2966.2008.13596.x. 
  8. ^ Wagman, Morton (2003). Lost Stars. The McDonald & Woodward Publishing Company. p. 106. ISBN 0-939923-78-5. 
  9. ^ Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York: Dover Publications Inc., p. 162, ISBN 0-486-21079-0, retrieved 2010-12-12 
  10. ^ (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.
  11. ^ (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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