Pi Ceti

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Pi Ceti
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cetus
Right ascension 02h 44m 07.4s
Declination −13° 51′ 31″
Apparent magnitude (V) 4.24
Distance 442 ly
(135.58 pc)
Spectral type B7V
Other designations
89 Ceti, HD 17081, HR 811, SAO 148575, FK5 97, NSV --, BD -14 519, HIP 12770.[1]

Pi Ceti (π Ceti, π Cet) is a Class B7, fourth-magnitude star in the constellation Cetus. Pi Ceti is a blue main-sequence star located about 440 light-years from Earth. It has about 8.1 times the radius of the Sun.[2]


This star, along with ε Cet, ρ Cet and σ Cet, was Al Sufi's Al Sadr al Ḳaiṭos, the Whale's Breast [3]

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 :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[4]

In Chinese, 天苑 (Tiān Yuàn), meaning Celestial Meadows, refers to an asterism consisting of π Ceti, γ Eridani, π Eridani, δ Eridani, ε Eridani, ζ Eridani, η Eridani, τ1 Eridani, τ2 Eridani, τ3 Eridani, τ4 Eridani, τ5 Eridani, τ6 Eridani, τ7 Eridani, τ8 Eridani and τ9 Eridani.[5] Consequently, δ Ceti itself is known as 天苑七 (Tiān Yuàn qī, English: the Seventh Star of Celestial Meadows.)[6]


  1. ^ HD 17081 -- Star, SIMBAD Astronomical Database, retrieved 2006-11-08 
  2. ^ Underhill, A. B. et al. (November 1979), Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars, Monthly Notices of the Royal Astronomical Society 189: 601–605, Bibcode:1979MNRAS.189..601U, doi:10.1093/mnras/189.3.601 
  3. ^ Star Name - R.H.Allen p. 160
  4. ^ 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
  5. ^ (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.
  6. ^ (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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