Lambda Persei


λ Persei, Latinized as Lambda Persei, is a star in the northern constellation of Perseus. It is visible to the naked eye as a faint, white-hued point of light with an apparent visual magnitude of 4.29.[2] This object is located approximately 422 light years from the Sun based on parallax,[1] and is drifting further away with a radial velocity of +6 km/s.[4]

Lambda Persei
Perseus constellation map.svg
Red circle.svg
Location of λ Persei (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Perseus
Right ascension 04h 06m 35.04360s[1]
Declination 50° 21′ 04.5500″[1]
Apparent magnitude (V) 4.29[2]
Spectral type A0IVn[3]
U−B color index −0.04[2]
B−V color index +0.02[2]
Radial velocity (Rv)+6.1±2.0[4] km/s
Proper motion (μ) RA: −12.75[1] mas/yr
Dec.: −35.60[1] mas/yr
Parallax (π)7.73 ± 0.22 mas[1]
Distance420 ± 10 ly
(129 ± 4 pc)
Absolute magnitude (MV)−1.31[5]
Radius3.1[6] R
Luminosity348[5] L
Surface gravity (log g)4.05[7] cgs
Temperature10,585[7] K
Metallicity [Fe/H]+0.01[7] dex
Rotational velocity (v sin i)196[8] km/s
Age345[9] Myr
Other designations
λ Per, 47 Persei, BD+49°1101, FK5 1113, GC 4924, HD 25642, HIP 19167, HR 1261, SAO 24412[10]
Database references
λ Persei in optical light

This object has a stellar classification of A0IVn,[3] matching an A-type subgiant star with "nebulous" lines due to rapid rotation. It is spinning with a projected rotational velocity of 196 km/s,[8] which is giving the star an equatorial bulge that is an estimated 16% larger than the polar radius.[11] Unusually for a star of this type, spectra show weak emission features among the Hydrogen lines, which may be due to plage regions on the surface caused by an implied magnetic field.[12] The star is 345[9] million years old and is radiating 348[5] times the luminosity of the Sun from its photosphere at an effective temperature of 10,585 K.[7]

In Chinese astronomy, Lambda Persei is called 積水, Pinyin: Jīshuǐ, meaning Stored Water, because this star is marking itself and stand alone in Stored Water asterism, Stomach mansion (see : Chinese constellation).[13]


  1. ^ a b c d e f Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600. Vizier catalog entry
  2. ^ a b c d Ducati, J. R. (2002). "Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  3. ^ a b Cowley, A.; et al. (April 1969). "A study of the bright A stars. I. A catalogue of spectral classifications". Astronomical Journal. 74: 375–406. Bibcode:1969AJ.....74..375C. doi:10.1086/110819.
  4. ^ a b Wilson, R. E. (1953). General Catalogue of Stellar Radial Velocities. Carnegie Institution for Science. Bibcode:1953GCRV..C......0W. LCCN 54001336.
  5. ^ a b c 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. ^ Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics (Third ed.), 367 (2): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754
  7. ^ a b c d Wu, Yue; et al. (2010). "Coudé-feed stellar spectral library – atmospheric parameters". Astronomy & Astrophysics. 525: A71. arXiv:1009.1491. Bibcode:2011A&A...525A..71W. doi:10.1051/0004-6361/201015014. S2CID 53480665.
  8. ^ a b Hoffleit, D.; Warren, W. H. (1995). "Bright Star Catalogue". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H (5th Revised ed.). 5050. Bibcode:1995yCat.5050....0H.
  9. ^ a b Gontcharov, G. A. (November 2012). "Spatial distribution and kinematics of OB stars". Astronomy Letters. 38 (11): 694–706. arXiv:1606.09028. Bibcode:2012AstL...38..694G. doi:10.1134/S1063773712110035. S2CID 119108982.
  10. ^ "lam Per". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-22.
  11. ^ Belle, G. T. (2012). "Interferometric observations of rapidly rotating stars". The Astronomy and Astrophysics Review. 20: 51. arXiv:1204.2572. Bibcode:2012A&ARv..20...51V. doi:10.1007/s00159-012-0051-2. S2CID 119273474.
  12. ^ Underhill, Anne B. (November 1991). "Lambda Persei: an Unusual B9 IV Star". Publications of the Astronomical Society of the Pacific. 103: 1176. Bibcode:1991PASP..103.1176U. doi:10.1086/132937.
  13. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日