Zeta Leonis

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Adhafera, ζ Leo
Diagram showing star positions and boundaries of the Leo constellation and its surroundings
Cercle rouge 100%.svg

Adhafera is the ζ star in the lion's mane (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Leo
Right ascension 10h 16m 41.41597s[1]
Declination +23° 25′ 02.3221″[1]
Apparent magnitude (V) 3.33[2]
Spectral type F0 III[3][4]
U−B color index +0.07[2]
B−V color index +0.30[2]
Variable type Suspected
Radial velocity (Rv) -15.6[5] km/s
Proper motion (μ) RA: +18.39[1] mas/yr
Dec.: -6.84[1] mas/yr
Parallax (π) 11.90 ± 0.18[1] mas
Distance 274 ± 4 ly
(84 ± 1 pc)
Mass 3[6] M
Radius 6[7] R
Luminosity 85[7] L
Surface gravity (log g) 3.0[7] cgs
Temperature 6,792[7] K
Metallicity [Fe/H] –0.03[8] dex
Rotational velocity (v sin i) 72.4[7] km/s
Other designations
Adhafera, Aldhafera, Adhafara, ζ Leo, 36 Leo, HR 4031, BD +24°2209, HD 89025, FK5 384, HIP 50335, SAO 81265, GC 14107, NSV 04804, WDS 10167+2325A.[9]
Database references

Zeta Leonis (ζ Leo, ζ Leonis) is a third-magnitude star in the constellation Leo, the lion. It has the traditional name Adhafera (Aldhafera, Adhafara), from the Arabic الضفيرة al-ðafīrah "the braid/curl", a reference to its position in the lion's mane. It forms the second star (after Gamma Leonis) in the blade of "The Sickle", which is an asterism formed from the head of Leo.[10]


Adhafera is a giant star with a stellar classification of F0 III. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[4] Its apparent magnitude is +3.44, making it relatively faint for a star that is visible to the naked eye. Nevertheless, it shines with 85 times the luminosity of the Sun.[7] Adhafera has about three times the Sun's mass[6] and six times the radius of the Sun.[7] Parallax measurements from the Hipparcos satellite yield an estimated distance to Adhafera of 274 light-years (84 parsecs)[1] from Earth.

Adhafera forms a double star with an optical companion that has an apparent magnitude of 5.90. Known as 35 Leo, this star is separated from Adhafera by 325.9 arcseconds along a position angle of 340°.[11][12] The two stars do not form a binary star system as 35 Leo is only 100 light years from Earth.

See also[edit]


  1. ^ a b c d e f van Leeuwen, F. (November 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 
  2. ^ a b c Fernie, J. D. (May 1983), "New UBVRI photometry for 900 supergiants", Astrophysical Journal Supplement Series 52: 7–22, Bibcode:1983ApJS...52....7F, doi:10.1086/190856 
  3. ^ Montes, D.; et al. (November 2001), "Late-type members of young stellar kinematic groups - I. Single stars", Monthly Notices of the Royal Astronomical Society 328 (1): 45–63, arXiv:astro-ph/0106537, Bibcode:2001MNRAS.328...45M, doi:10.1046/j.1365-8711.2001.04781.x 
  4. ^ a b Garrison, R. F. (December 1993), "Anchor Points for the MK System of Spectral Classification", Bulletin of the American Astronomical Society 25: 1319, Bibcode:1993AAS...183.1710G, retrieved 2012-02-04 
  5. ^ Wielen, R.; et al. (1999), Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions (35), Astronomisches Rechen-Institut Heidelberg, Bibcode:1999VeARI..35....1W 
  6. ^ a b Kaler, James B., "ADHAFERA (Zeta Leonis)", Stars (University of Illinois), retrieved 2010-05-12 
  7. ^ a b c d e f g Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209 
  8. ^ Gray, R. O.; Graham, P. W.; Hoyt, S. R. (April 2001), "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. II. Basic Parameters of Program Stars and the Role of Microturbulence", The Astronomical Journal 121 (4): 2159–2172, Bibcode:2001AJ....121.2159G, doi:10.1086/319957 
  9. ^ "zet Leo -- Variable Star", SIMBAD (Centre de Données astronomiques de Strasbourg), retrieved 2010-05-12 
  10. ^ Proctor, Mary (July 1896), "Evenings with the Stars", Popular Astronomy 4: 565 
  11. ^ "CCDM (Catalog of Components of Double & Multiple stars (Dommanget+ 2002)", VizieR (Centre de Données astronomiques de Strasbourg), retrieved 2010-05-12 
  12. ^ Adhafera, Alcyone Bright Star Catalogue, retrieved 2010-05-12