Pi Persei


π Persei, Latinized as Pi Persei, is a single[11] star in the northern constellation of Perseus. It has the traditional name Gorgonea Secunda /ɡɔːrɡəˈnə 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]

Pi Persei
Perseus constellation map.svg
Red circle.svg
Location of π Persei (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Perseus
Right ascension 02h 58m 45.66858s[1]
Declination +39° 39′ 45.8212″[1]
Apparent magnitude (V) 4.70[2]
Spectral type A2Vn[3]
U−B color index +0.12[2]
B−V color index +0.06[2]
Radial velocity (Rv)+14.2[4] km/s
Proper motion (μ) RA: +26.224[1] mas/yr
Dec.: −41.899[1] mas/yr
Parallax (π)10.7797 ± 0.2794 mas[1]
Distance303 ± 8 ly
(93 ± 2 pc)
Absolute magnitude (MV)−0.21[5]
Mass2.07[6] M
Radius4.8[7] R
Luminosity170[8] L
Surface gravity (log g)3.53[6] cgs
Temperature9,290[8] K
Rotational velocity (v sin i)186[8] km/s
Age272[6] Myr
Other designations
Gorgonea Secunda[9], π Per, 22 Persei, BD+39°681, FK5 2207, GC 3567, HD 18411, HIP 13879, HR 879, SAO 56047[10]
Database references

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 272[6] million years old with double the mass of the Sun.[6] It has 4.8[7] times the Sun's radius and is radiating 170[8] times the luminosity of the Sun from its photosphere at an effective temperature of 9,290 K.[8]


  1. ^ a b c d e f 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. ^ a b c d 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. ^ a b 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. ^ a b 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.
  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. ^ a b c d e 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. ^ a b 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. ^ a b c d e f 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.
  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.