Astronomy:Epsilon Leonis

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Short description: Star in the constellation Leo
Epsilon Leonis
Location of ε Leonis (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Leo
Right ascension  09h 45m 51.07330s[1]
Declination +23° 46′ 27.3208″[1]
Apparent magnitude (V) 2.98[2]
Characteristics
Evolutionary stage giant[3]
Spectral type G1 IIIa[4]
U−B color index +0.47[2]
B−V color index +0.808[5]
Variable type suspected[6]
Astrometry
Radial velocity (Rv)4.86 ± 0.33[5] km/s
Proper motion (μ) RA: –45.61[1] mas/yr
Dec.: –9.21[1] mas/yr
Parallax (π)13.22 ± 0.15[1] mas
Distance247 ± 3 ly
(75.6 ± 0.9 pc)
Absolute magnitude (MV)–1.49[3]
Details
Mass3.71±0.04[7] M☉
Radius21.03+0.31
−0.32[7] R☉
Luminosity282±13[8] L☉
Surface gravity (log g)2.36±0.05[8] cgs
Temperature5,314±17[8] K
Metallicity [Fe/H]−0.03±0.11[8] dex
Rotational velocity (v sin i)8.1[5] km/s
Age210±0[7] Myr
Other designations
Algenubi, Ras Elased Australis,[9] ε Leo, 17 Leo, BD+24°2129, FK5 367, GC 13443, HD 84441, HIP 47908, HR 3873, SAO 81004[10]
Database references
SIMBADdata

Epsilon Leonis (ε Leo, ε Leonis) is the fifth-brightest star in the constellation Leo, consistent with its Bayer designation Epsilon. It is known as Algenubi or Ras Elased Australis. Both names mean "the southern star of the lion's head". Australis is Latin for "southern" and Genubi is Arabic for "south".

Properties

Epsilon Leonis has a stellar classification of G1 III,[4] with the luminosity class of III indicating that, it has evolved into a giant star. However, Usenko (2017) classified it as a yellow supergiant.[11] It is much larger and brighter than the Sun with a luminosity 282 times[8] and a radius 21 times solar.[7] Consequently, its absolute magnitude is actually –1.49,[3] making it one of the more luminous stars in the constellation, significantly more than Regulus. Its apparent brightness, though, is only 2.98.[2] Given its distance of about 247 light-years (76 parsecs), the star is more than three times the distance from the Sun than Regulus. At this distance, the visual magnitude of Epsilon Leonis is reduced by 0.03 as a result of extinction caused by intervening gas and dust.[3]

Epsilon Leonis exhibits the characteristics of a Cepheid-like variable, changing by an amplitude of 0.3 magnitude every few days.[12][9] It has around four times the mass of the Sun and a projected rotational velocity of 8.1 km s−1.[5] Based upon its iron abundance, the metallicity of this star's outer atmosphere is only around 52% of the Sun's. That is, the abundance of elements other than hydrogen and helium is about half that in the Sun.[5]

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 van Leeuwen, Floor (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V  Note: see VizieR catalogue I/311.
  2. ↑ 2.0 2.1 2.2 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J 
  3. ↑ 3.0 3.1 3.2 3.3 Takeda, Yoichi; Sato, Bun'ei; Murata, Daisuke (August 2008), "Stellar parameters and elemental abundances of late-G giants", Publications of the Astronomical Society of Japan 60 (4): 781–802, doi:10.1093/pasj/60.4.781, Bibcode: 2008PASJ...60..781T 
  4. ↑ 4.0 4.1 Keenan, Philip C.; McNeil, Raymond C. (1989-10-01), "The Perkins Catalog of Revised MK Types for the Cooler Stars", The Astrophysical Journal Supplement Series 71: 245, doi:10.1086/191373, ISSN 0067-0049, Bibcode: 1989ApJS...71..245K 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 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, doi:10.1088/0004-6256/135/1/209, Bibcode: 2008AJ....135..209M 
  6. ↑ Samus, N. N. et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S 1. Bibcode: 2009yCat....102025S. 
  7. ↑ 7.0 7.1 7.2 7.3 Baines, Ellyn K. et al. (2018), "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer", The Astronomical Journal 155 (1): 30, doi:10.3847/1538-3881/aa9d8b, Bibcode: 2018AJ....155...30B .
  8. ↑ 8.0 8.1 8.2 8.3 8.4 Soubiran, C.; Creevey, O. L.; Lagarde, N.; Brouillet, N.; Jofré, P.; Casamiquela, L.; Heiter, U.; Aguilera-Gómez, C. et al. (2024-02-01), "Gaia FGK benchmark stars: Fundamental Teff and log g of the third version", Astronomy and Astrophysics 682: A145, doi:10.1051/0004-6361/202347136, ISSN 0004-6361, Bibcode: 2024A&A...682A.145S  Epsilon Leonis' database entry at VizieR.
  9. ↑ 9.0 9.1 Kaler, James B., "ALGENUBI (Epsilon Leonis)", Stars (University of Illinois), http://stars.astro.illinois.edu/sow/algenubi.html, retrieved 2010-05-10 
  10. ↑ "eps Leo". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=eps+Leo. 
  11. ↑ Template:Ciation
  12. ↑ Andrievsky, S. M. (July 1998), "BA II lines as luminosity indicators: s-Cepheids and non-variable supergiants", Astronomische Nachrichten 319 (4): 239–240, doi:10.1002/asna.2123190405, Bibcode: 1998AN....319..239A 



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