Xi Persei

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Perseus constellation map.svg
Red circle.svg
Location of ξ Persei (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Perseus
Right ascension  03h 58m 57.90229s[1]
Declination +35° 47′ 27.7132″[1]
Apparent magnitude (V) 4.04[2]
Spectral type O7.5III(n)((f))[3]
U−B color index −0.93[2]
B−V color index +0.02[2]
Variable type slightly variable[4]
Radial velocity (Rv)65.40[5] km/s
Proper motion (μ) RA: 3.62[1] mas/yr
Dec.: 1.74[1] mas/yr
Parallax (π)2.62 ± 0.51[1] mas
Distanceapprox. 1,200 ly
(approx. 380 pc)
Absolute magnitude (MV)−5.50[3]
Mass26[3]-36[6] M
Radius14[6] R
Luminosity263,000[3] L
Surface gravity (log g)3.5[3] cgs
Temperature35,000[6] K
Rotational velocity (v sin i)220[3] km/s
Age~7[7] Myr
Other designations
46 Per, HR 1228, HD 24912, FK5 148, SAO 56856, HIP 18614, BD+35°775
Database references

Xi Persei (ξ Persei, abbreviated Xi Per, ξ Per), formally named Menkib /ˈmɛŋkɪb/,[8][9] is a star in the constellation of Perseus. Based upon parallax measurements taken during the Hipparcos mission, it is approximately 1,200 light-years from the Sun.


ξ Persei (Latinised to Xi Persei) is the star's Bayer designation.

It bore the traditional name Menkib, Menchib, Menkhib or Al Mankib, from Mankib al Thurayya (Arabic for "shoulder" [of the Pleiades]). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[10] to catalogue and standardize proper names for stars; the WGSN approved the name Menkib for this star on 12 September 2016 and it is now so included in the List of IAU-approved Star Names.[9]

In Chinese, 卷舌 (Juǎn Shé), meaning Rolled Tongue, refers to an asterism consisting of Xi Persei, Nu Persei, Epsilon Persei, Zeta Persei, Omicron Persei and 40 Persei.[11] Consequently, the Chinese name for Xi Persei itself is 卷舌三 (Juǎn Shé sān, "the Third Star of Rolled Tongue").[12]


Xi Persei has an apparent magnitude of +4.06 and is classified as a blue giant (spectral class O7.5III). It is intrinsically 12,700 times brighter than the Sun with absolute magnitude −5.5 in the V band. If the ultraviolet light that emanates from Menkib is included, its total bolometric luminosity is 263,000 times that of the Sun.

The star has a mass of some 30 solar masses and a surface temperature of 35,000 kelvins, making it one of the hottest stars that can be seen with the naked eye; the fluorescence of the California Nebula (NGC 1499) is due to this star's prodigious radiation.[7] It is a member of the Perseus OB2 association of co-moving stars, but may be a runaway star since it is now separated by 200 pc from the association's center and has an unusually high radial velocity.[13]


  1. ^ a b c d e Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
  2. ^ a b c 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: 0. Bibcode:2002yCat.2237....0D.
  3. ^ a b c d e f Repolust, T.; Puls, J.; Herrero, A. (2004). "Stellar and wind parameters of Galactic O-stars. The influence of line-blocking/blanketing". Astronomy and Astrophysics. 415 (1): 349–376. Bibcode:2004A&A...415..349R. doi:10.1051/0004-6361:20034594.
  4. ^ Ramiaramanantsoa, Tahina; Moffat, Anthony F. J.; Chené, André-Nicolas; Richardson, Noel D.; Henrichs, Huib F.; Desforges, Sébastien; Antoci, Victoria; Rowe, Jason F.; Matthews, Jaymie M.; Kuschnig, Rainer; Weiss, Werner W.; Sasselov, Dimitar; Rucinski, Slavek M.; Guenther, David B. (2014). "MOST detects corotating bright spots on the mid-O-type giant ξ Persei" (PDF). Monthly Notices of the Royal Astronomical Society. 441: 910. arXiv:1403.7843. Bibcode:2014MNRAS.441..910R. doi:10.1093/mnras/stu619.
  5. ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
  6. ^ a b c Krticka, J.; Kubat, J. (2010). "Comoving frame models of hot star winds. I. Test of the Sobolev approximation in the case of pure line transitions". Astronomy and Astrophysics. 519: A50. arXiv:1005.0258. Bibcode:2010A&A...519A..50K. doi:10.1051/0004-6361/201014111.
  7. ^ a b Hoogerwerf, R.; De Bruijne, J. H. J.; De Zeeuw, P. T. (2001). "On the origin of the O and B-type stars with high velocities. II. Runaway stars and pulsars ejected from the nearby young stellar groups". Astronomy and Astrophysics. 365 (2): 49. arXiv:astro-ph/0010057. Bibcode:2001A&A...365...49H. doi:10.1051/0004-6361:20000014.
  8. ^ Davis, George A. (1944). "The pronunciations, derivations, and meanings of a selected list of star names". Popular Astronomy. 52: 8–30.
  9. ^ a b "Naming Stars". IAU.org. Retrieved 16 December 2017.
  10. ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 2016.
  11. ^ (in 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.
  12. ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2008-10-25 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  13. ^ Lesh, J. R. (September 1969). "Internal motions in the associations II Per and I Lac". Astronomical Journal. 74: 891–898. Bibcode:1969AJ.....74..891L. doi:10.1086/110878.

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