Eta Leonis

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Eta Leonis
Leo constellation map.svg
Red circle.svg

Location of η Leo (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Leo
Right ascension 10h 07m 19.95186s[1]
Declination 16° 45′ 45.592″[1]
Apparent magnitude (V) 3.486[2]
Spectral type A0 Ib[2]
U−B color index −-0.206[2]
B−V color index −0.026[2]
Radial velocity (Rv) 1.40[3] km/s
Proper motion (μ) RA: −2.80[1] mas/yr
Dec.: −1.82[1] mas/yr
Parallax (π) 2.57 ± 0.16[1] mas
Distance 1,270 ± 80 ly
(390 ± 20 pc)
Absolute magnitude (MV) -5.54[4]
Mass 10[5] M
Radius 47[4] R
Luminosity 19,000[5] L
Surface gravity (log g) 2.00[5] cgs
Temperature 9,600[2] K
Metallicity -0.04[4]
Rotational velocity (v sin i) 2[2] km/s
Age 25[5] Myr
Other designations
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 doesn't have a proper name. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[6]


Eta Leonis is a white supergiant with the stellar classification A0Ib. Though its apparent magnitude is 3.5, making it a relatively dim star to the naked eye, it is nearly 20,000 times more luminous than the Sun, with an absolute magnitude of -5.60. The Hipparcos astrometric data has estimated the distance of Eta Leonis to be roughly 400 parsecs from Earth, or 1,300 light years away.

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

See also[edit]


  1. ^ a b c d e Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752free to read. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d e f Firnstein, M.; Przybilla, N. (2012). "Quantitative spectroscopy of Galactic BA-type supergiants. I. Atmospheric parameters". Astronomy & Astrophysics. 543: A80. arXiv:1207.0308free to read. Bibcode:2012A&A...543A..80F. doi:10.1051/0004-6361/201219034. 
  3. ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. 
  4. ^ a b c Przybilla, N.; Butler, K.; Becker, S. R.; Kudritzki, R. P. (2006). "Quantitative spectroscopy of BA-type supergiants". Astronomy and Astrophysics. 445 (3): 1099. arXiv:astro-ph/0509669free to read. Bibcode:2006A&A...445.1099P. doi:10.1051/0004-6361:20053832. 
  5. ^ a b c d Tanrıverdi, Taner (2013). "Elemental abundances of the supergiant stars σ Cygnus and η Leonis". New Astronomy. 25: 50. arXiv:1512.04557free to read. Bibcode:2013NewA...25...50T. doi:10.1016/j.newast.2013.03.013. 
  6. ^ 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 

External links[edit]