Beta Leporis

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Beta Leporis
Diagram showing star positions and boundaries of the Lepus constellation and its surroundings
Cercle rouge 100%.svg
Location of β Leporis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Lepus
Right ascension 05h 28m 14.72316s[1]
Declination −20° 45′ 33.9878″[1]
Apparent magnitude (V) 2.84[2]
Spectral type G5 II[3]
U−B color index +0.47[2]
B−V color index +0.82[2]
R−I color index +0.44[4]
Radial velocity (Rv)−13.6 ± 0.9[5] km/s
Proper motion (μ) RA: −5.02[1] mas/yr
Dec.: −85.92[1] mas/yr
Parallax (π)20.34 ± 0.18 mas[1]
Distance160 ± 1 ly
(49.2 ± 0.4 pc)
Absolute magnitude (MV)−0.65[6]
Mass3.5 ± 0.1[7] M
Radius16[8] R
Luminosity171[9] L
Surface gravity (log g)2.60 ± 0.03[7] cgs
Temperature5,450 ± 100[7] K
Metallicity [Fe/H]+0.05[10] dex
Rotational velocity (v sin i)11[11] km/s
Age240[7] Myr
Other designations
Nihal, β Lep, Beta Leporis, Beta Lep, 9 Leporis, 9 Lep, BD−20 1096, FK5 204, GC 6762, HD 36079, HIP 25606, HR 1829, PPM 248938, SAO 170457, WDS 05282-2046A.[3]
Database references

Beta Leporis (β Leporis, abbreviated Beta Lep, β Lep), formally named Nihal /ˈn.æl/,[12][13] is the second brightest star in the constellation of Lepus.[8]


Beta Leporis is the star's Bayer designation. It is also known by the traditional named Nihal, Arabic for "quenching their thirst". The occasional spelling Nibal appears to be due to a misreading.[14] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[15] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[16] included a table of the first two batches of names approved by the WGSN; which included Nihal for this star.

In Chinese, (), meaning Toilet, refers to an asterism consisting of β Leporis, α Leporis, γ Leporis and δ Leporis.[17] Consequently, the Chinese name for β Leporis itself is 廁二 (Cè èr), "the Second Star of Toilet".[18]


Based on parallax measurements from the Hipparcos astrometry satellite,[19] this star is located about 160 light-years (49 parsecs) from the Earth. It has an apparent visual magnitude of 2.84 and a stellar classification of G5 II. The mass of this star is 3.5 times the mass of the Sun and it is about 240 million years old,[7] which is sufficient time for a star this massive to consume the hydrogen at its core and evolve away from the main sequence, becoming a G-type bright giant.[3]

This is a double star system and may be a binary, whereby the second star has a brightness of 7.34 mag [1]. Using adaptive optics on the AEOS telescope at Haleakala Observatory, the pair was found to be separated by an angle of 2.58 arcseconds at a position angle of 1.4°.[20] Component B has been observed to fluctuate in brightness and is catalogued as suspected variable star NSV 2008.[21]


  1. ^ a b c d e 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. S2CID 18759600.
  2. ^ a b c 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. ^ a b c "CCDM J05283-2046AB -- Double or multiple star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2011-12-27
  4. ^ HR 1829, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line November 18, 2008.
  5. ^ Evans, D. S. (1967), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick (eds.), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30 held at the University of Toronto 20-24 June, 1966, vol. 30, Academic Press, London, p. 57, Bibcode:1967IAUS...30...57E
  6. ^ 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.
  7. ^ a b c d e Lyubimkov, Leonid S.; et al. (February 2010), "Accurate fundamental parameters for A-, F- and G-type Supergiants in the solar neighbourhood", Monthly Notices of the Royal Astronomical Society, 402 (2): 1369–1379, arXiv:0911.1335, Bibcode:2010MNRAS.402.1369L, doi:10.1111/j.1365-2966.2009.15979.x, S2CID 119096173
  8. ^ a b Kaler, James B., "Nihal", Stars, archived from the original on 2008-12-10, retrieved 2008-11-18
  9. ^ Mallik, Sushma V. (December 1999), "Lithium abundance and mass", Astronomy and Astrophysics, 352: 495–507, Bibcode:1999A&A...352..495M
  10. ^ Luck, R. Earle; Wepfer, Gordon G. (November 1995), "Chemical Abundances for F and G Luminosity Class II Stars", Astronomical Journal, 110: 2425, Bibcode:1995AJ....110.2425L, doi:10.1086/117702
  11. ^ Bernacca, P. L.; Perinotto, M. (1970). "A catalogue of stellar rotational velocities". Contributi Osservatorio Astronomico di Padova in Asiago. 239 (1): 1. Bibcode:1970CoAsi.239....1B.
  12. ^ Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
  13. ^ "IAU Catalog of Star Names". Retrieved 28 July 2016.
  14. ^ Allen, Richard Hinckley (1899), Star-names and Their Meanings, New York: G. E. Steichert, pp. 265, 269
  15. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  16. ^ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 2016.
  17. ^ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  18. ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2008-10-25 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  19. ^ Perryman, Michael (2010), The Making of History's Greatest Star Map, Astronomers' Universe, Heidelberg: Springer-Verlag,, doi:10.1007/978-3-642-11602-5, ISBN 978-3-642-11601-8
  20. ^ Roberts, Lewis C., Jr. (May 2011), "Astrometric and photometric measurements of binary stars with adaptive optics: observations from 2002", Monthly Notices of the Royal Astronomical Society, 413 (2): 1200–1205, arXiv:1012.3383, Bibcode:2011MNRAS.413.1200R, doi:10.1111/j.1365-2966.2011.18205.x, S2CID 118398949
  21. ^ "NSV 2008, database entry", New Catalogue of Suspected Variable Stars, the improved version, Moscow, Russia.: Sternberg Astronomical Institute, retrieved 2008-11-18