Pi Persei

Pi Persei
Location of π Persei (circled)
Observation data
Epoch J2000      Equinox ICRS
Constellation Perseus
Right ascension 02h 58m 45.66858s
Declination +39° 39′ 45.8212″
Apparent magnitude (V) 4.70
Characteristics
Spectral type A2Vn
U−B color index +0.12
B−V color index +0.06
Astrometry
Radial velocity (Rv)+14.2 km/s
Proper motion (μ) RA: +26.224 mas/yr
Dec.: −41.899 mas/yr
Parallax (π)10.7797±0.2794 mas
Distance303 ± 8 ly
(93 ± 2 pc)
Absolute magnitude (MV)−0.21
Details
Mass2.07 M☉
Radius4.8 R☉
Luminosity170 L☉
Surface gravity (log g)3.53 cgs
Temperature9,290 K
Rotational velocity (v sin i)186 km/s
Age272 Myr
Other designations
Gorgonea Secunda, π Per, 22 Persei, BD+39°681, FK5 2207, GC 3567, HD 18411, HIP 13879, HR 879, SAO 56047
Database references
SIMBADdata

π Persei, Latinized as Pi Persei, is a single 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. 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.

This object is an A-type main-sequence star with a stellar classification of A2Vn, where the 'n' suffix indicates broad (nebulous) lines due to rapid rotation. It is spinning with a projected rotational velocity of 186 km/s, which is creating an equatorial bulge that is 6% wider than the polar radius. The star is 272 million years old with double the mass of the Sun. It has 4.8 times the Sun's radius and is radiating 170 times the luminosity of the Sun from its photosphere at an effective temperature of 9,290 K.

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

References

  1. 1 2 3 4 5 6 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. 1 2 3 4 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. 1 2 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. 1 2 Wilson, R. E. (1953). General Catalogue of Stellar Radial Velocities. Papers of the Mount Wilson Observatory. Carnegie Institution for Science. Bibcode:1953GCRV..C......0W. LCCN 54001336. OCLC 1847567.
  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. 1 2 3 4 5 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. 1 2 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. 1 2 3 4 5 6 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. 1 2 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.