Article · Wikipedia archive · Last revised Jul 28, 2026

Pi Persei

π Persei, Latinized as Pi Persei, is a single star in the northern constellation of Perseus. It has the traditional name Gorgonea Secunda, the second of three Gorgons in the mythology of the hero Perseus. This star has a white hue and is faintly visible to the naked eye with an apparent visual magnitude of +4.7. It is located at a distance of approximately 303 light years from the Sun based on parallax, and is moving further away with a radial velocity of +14 km/s.

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Pi Persei
Location of π Persei (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Perseus
Right ascension 02h 58m 45.66858s1
Declination +39° 39′ 45.8212″1
Apparent magnitude (V) 4.702
Characteristics
Spectral type A2Vn3
U−B color index +0.122
B−V color index +0.062
Astrometry
Radial velocity (Rv)+14.24 km/s
Proper motion (μ) RA: +26.2241 mas/yr
Dec.: −41.8991 mas/yr
Parallax (π)10.7797±0.2794 mas1
Distance303 ± 8 ly
(93 ± 2 pc)
Absolute magnitude (MV)−0.215
Details
Mass2.076 M☉
Radius4.87 R☉
Luminosity1708 L☉
Surface gravity (log g)3.536 cgs
Temperature9,2908 K
Rotational velocity (v sin i)1868 km/s
Age2726 Myr
Other designations
Gorgonea Secunda9, π Per, 22 Persei, BD+39°681, FK5 2207, GC 3567, HD 18411, HIP 13879, HR 879, SAO 5604710
Database references
SIMBADdata

π Persei, Latinized as Pi Persei, is a single11 star in the northern constellation of Perseus. It has the traditional name Gorgonea Secunda /ɡɔːrɡəˈniːə sɪˈkʌndə/, the second of three Gorgons in the mythology of the hero Perseus.12 This star has a white hue and is faintly visible to the naked eye with an apparent visual magnitude of +4.7.2 It is located at a distance of approximately 303 light years from the Sun based on parallax,1 and is moving further away with a radial velocity of +14 km/s.4

This object is an A-type main-sequence star with a stellar classification of A2Vn,3 where the 'n' suffix indicates broad (nebulous) lines due to rapid rotation. It is spinning with a projected rotational velocity of 186 km/s,8 which is creating an equatorial bulge that is 6% wider than the polar radius.13 The star is 2726 million years old with double the mass of the Sun.6 It has 4.87 times the Sun's radius and is radiating 1708 times the luminosity of the Sun from its photosphere at an effective temperature of 9,290 K.8

In Chinese astronomy, this star is named Jīshī (Chinese: 積屍), meaning Heap of Corpses.14 R. H. Allen transliterated this name as Tseih She and wrongly identified it with Algol.915

References

References

  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  3. Abt, Helmut A.; Morrell, Nidia I. (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". Astrophysical Journal Supplement. 99: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182.
  4. Wilson, R. E. (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Carnegie Institution for Science. Bibcode:1953GCRV..C......0W. ISBN 9780598216885. LCCN 54001336. {{cite journal}}: ISBN / Date incompatibility (help)
  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. S2CID 119257644. Vizier catalog entry
  6. David, Trevor J.; Hillenbrand, Lynne A. (2015). "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv:1501.03154. Bibcode:2015ApJ...804..146D. doi:10.1088/0004-637X/804/2/146. S2CID 33401607. Vizier catalog entry
  7. Allende Prieto, C.; Lambert, D. L. (1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: Masses, radii and effective temperatures". Astronomy and Astrophysics. 352: 555–562. arXiv:astro-ph/9911002. Bibcode:1999A&A...352..555A. Vizier catalog entry
  8. Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars". Astronomy & Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691. S2CID 55586789. Vizier catalog entry
  9. Allen, Richard Hinckley (1899). Star-names and Their Meanings. G.E. Stechert. p. 334. Also available online here
  10. "pi Per". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-12.
  11. 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. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
  12. Kaler, James B. (November 21, 2014). "Pi Persei". STARS. Retrieved 2019-10-12.
  13. van Belle, Gerard T. (March 2012). "Interferometric observations of rapidly rotating stars". The Astronomy and Astrophysics Review. 20 (1) 51. arXiv:1204.2572. Bibcode:2012A&ARv..20...51V. doi:10.1007/s00159-012-0051-2. S2CID 119273474.
  14. "AEEA 天文教育資訊網" [Activities of Exhibition and Education in Astronomy] (in Chinese). Archived from the original on 24 March 2008.
  15. Ridpath, Ian. "Star Tales - Perseus". Retrieved 22 July 2025.