Beta Leporis

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

β Leporis
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]
Characteristics
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]
Astrometry
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]
Details
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
SIMBADdata

Nomenclature

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, 廁 (Cè), 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]

Properties

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 the 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.[20] 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°.[21] Component B has been observed to fluctuate in brightness and is catalogued as suspected variable star NSV 2008.[22]

References
  1. 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. 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. "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. 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. 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, Bibcode:2010mhgs.book.....P, doi:10.1007/978-3-642-11602-5, ISBN 978-3-642-11601-8
  20. "Nihal - β Leporis (beta Leporis) - Star in Lepus | TheSkyLive.com". theskylive.com. Retrieved 2023-03-28.
  21. 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{{citation}}: CS1 maint: multiple names: authors list (link)
  22. "NSV 2008, database entry", New Catalogue of Suspected Variable Stars, the improved version, Moscow, Russia.: Sternberg Astronomical Institute, retrieved 2008-11-18
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