Rho Ceti

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Rho Ceti
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cetus
Right ascension  02h 25m 57.00560s[1]
Declination −12° 17′ 25.7104″[1]
Apparent magnitude (V) 4.885[2]
Spectral type A0 V[3]
U−B color index +0.001[2]
B−V color index −0.037[2]
Radial velocity (Rv)+18.9±2.0[4] km/s
Proper motion (μ) RA: −11.28[1] mas/yr
Dec.: −9.48[1] mas/yr
Parallax (π)7.15 ± 0.26[1] mas
Distance460 ± 20 ly
(140 ± 5 pc)
Absolute magnitude (MV)−0.85[5]
Radius3.1[6] R
Luminosity178[7] L
Temperature8,905[7] K
Rotational velocity (v sin i)219[8] km/s
Other designations
ρ Cet, 72 Cet, BD−12° 451, FK5 1066, HD 15130, HIP 11345, HR 708, SAO 148385.[9]
Database references

Rho Ceti , Latinized from ρ Ceti, is the Bayer designation for a star in the equatorial constellation of Cetus. It is faintly visible to the naked eye with an apparent visual magnitude of 4.885.[2] The distance to this star, based upon an annual parallax shift of 7.15 mas,[1] is around 460 light years.

This is an A-type main sequence star with a stellar classification of A0 V.[3] It is spinning rapidly with a projected rotational velocity of 219[8] km/s, giving the star an oblate shape with an equatorial bulge that is 10% larger than the polar radius.[10] The star has an estimated size 3.1[6] times the radius of the Sun and is radiating 178 times the solar luminosity from its outer atmosphere at an effective temperature of 8,905 K.[7]


This star, along with π Cet, ε Cet and σ Cet, was Al Sufi's Al Sadr al Ḳaiṭos, the Whale's Breast [11]

According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Sadr al Ḳaiṭos were the title for four stars :this star (ρ Cet) as Al Sadr al Ḳaiṭos I, σ Cet as Al Sadr al Ḳaiṭos II, ε Cet as Al Sadr al Ḳaiṭos III and π Cet as Al Sadr al Ḳaiṭos IV[12]

In Chinese, 芻蒿 (Chú Hāo), meaning Hay, refers to an asterism consisting of ρ Ceti, 77 Ceti, 67 Ceti, 71 Ceti, HD 14691[13] and ε Cet. Consequently, the Chinese name for ρ Ceti itself is 芻蒿一 (Chú Hāo yī, English: the First Star of Celestial Meadows.[14]


  1. ^ a b c d e f van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
  2. ^ a b c d Gutierrez-Moreno, Adelina; et al. (1966), "A System of photometric standards", Publ. Dept. Astron. Univ. Chile, Publicaciones Universidad de Chile, Department de Astronomy, 1: 1–17, Bibcode:1966PDAUC...1....1G.
  3. ^ a b Houk, Nancy; Smith-Moore, M. (1978), "Michigan catalogue of two-dimensional spectral types for the HD stars", Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Volume 4, Ann Arbor: Dept. of Astronomy, University of Michigan, 4, Bibcode:1988mcts.book.....H.
  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, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
  5. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015.
  6. ^ a b Pasinetti Fracassini, L. E.; Pastori, L.; Covino, S.; Pozzi, A. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics (3rd ed.), 367 (2): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
  7. ^ a b c McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
  8. ^ a b Royer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224.
  9. ^ "rho Cet". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-02-09.
  10. ^ Belle, G. T. (2012). "Interferometric observations of rapidly rotating stars". The Astronomy and Astrophysics Review. 20: 51. arXiv:1204.2572. Bibcode:2012A&ARv..20...51V. doi:10.1007/s00159-012-0051-2.
  11. ^ 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.
  12. ^ Jack W. Rhoads - Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars, Jet Propulsion Laboratory, California Institute of Technology; November 15, 1971
  13. ^ (in Chinese) 夢之大地 @ 國立成功大學 WebBBS DreamLand @ National Cheng Kung University WebBBS System
  14. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 12 日

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