Eta Leonis

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Eta Leonis
Leo IAU.svg
Cercle rouge 100%.svg

Location of η Leo (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Leo
Right ascension 10h 07m 19.9523s[1]
Declination 16° 45′ 45.592″[1]
Apparent magnitude (V) 3.511[1]
Spectral type A0 Ib[1]
U−B color index -0.21
B−V color index -0.03[2]
Variable type Eclipsing binary
Radial velocity (Rv) 3.3 [1] km/s
Proper motion (μ) RA: -1.94 [1] mas/yr
Dec.: -0.53 [1] mas/yr
Parallax (π) 1.53 ± 0.77[3] mas
Distance approx. 2,000 ly
(approx. 700 pc)
Absolute magnitude (MV) -5.60
Mass 10.8 [4] M
Radius 49.7 R
Luminosity 18,800 L
Temperature 9,770 K
Metallicity -0.04 Fe/H[5]
Rotation 23 km/s [6]
Age 3.5×107 [4] years
Other designations
Al Jabhah, η Leo, 30 Leo, HR 3975, BD +17°2171, HD 87737, FK5 379, HIP 49583, SAO 98955, GC 13899
Database references

Eta Leonis (η Leo, η Leonis) is a fourth-magnitude star in the constellation Leo. It is known as Al Jabhah, from the Arabic meaning 'the forehead'. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[7]


Eta Leonis is a white supergiant with the stellar classification A0Ib. Though its apparent magnitude is 3.51, making it a relatively dim star to the naked eye, it is 5,600 times more luminous than the Sun,[4] with an absolute magnitude of -5.60. The Hipparcos astrometric data has estimated the distance of Eta Leonis to be roughly 700 parsecs[3] from Earth, or 2,000 light years away.

There is evidence suggesting that Eta Leonis is part of a binary star system.[4]

See also[edit]


  1. ^ a b c d e f g "SIMBAD query result: eta Leo -- Variable Star". Centre de Données astronomiques de Strasbourg. Retrieved 2010-05-11. 
  2. ^ Nicolet, B. (October 1978). "Catalogue of homogeneous data in the UBV photoelectric photometric system". Astronomy and Astrophysics 34: 1–49. Bibcode:1978A&AS...34....1N. 
  3. ^ a b Perryman, M. A. C. et al. (1997), "The Hipparcos Catalogue", Astronomy & Astrophysics 323: L49–L52, Bibcode:1997A&A...323L..49P 
  4. ^ a b c d Professor James B. (Jim) Kaler. "ETA LEO (Eta Leonis)". University of Illinois. Retrieved 2010-05-11. 
  5. ^ Cenarro, A. J.; Peletier, R. F.; Sánchez-Blázquez, P.; Selam, S. O.; Toloba et al. (January 2007). "Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters". Monthly Notices of the Royal Astronomical Society 374 (2): 664–690. arXiv:astro-ph/0611618. Bibcode:2007MNRAS.374..664C. doi:10.1111/j.1365-2966.2006.11196.x. 
  6. ^ Royer, F.; Grenier, S.; Baylac, M.-O.; Gómez, A. E.; Zorec, J. (October 2002). "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i in the northern hemisphere". Astronomy and Astrophysics 393 (3): 897–911. arXiv:astro-ph/0205255. Bibcode:2002A&A...393..897R. doi:10.1051/0004-6361:20020943. 
  7. ^ 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 

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