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]
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[1] mas
Distance 160 ± 1 ly
(49.2 ± 0.4 pc)
Details
Mass 3.5 ± 0.1[6] M
Radius 16[7] R
Luminosity 171[8] L
Surface gravity (log g) 2.60 ± 0.03[6] cgs
Temperature 5,450 ± 100[6] K
Metallicity [Fe/H] +0.05[9] dex
Rotational velocity (v sin i) 11[10] km/s
Age 240[6] 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
SIMBAD data

Beta Leporis (Beta Lep, β Leporis, β Lep) is the second brightest star in the constellation of Lepus.[7] It is also known as Nihal,"quenching their thirst". The occasional spelling Nibal appears to be due to a misreading.[11]

Based on parallax measurements from the Hipparcos astrometry satellite,[12] 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,[6] 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. 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°.[13] Component B has been observed to fluctuate in brightness and is catalogued as suspected variable star NSV 2008. [14]

References[edit]

  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. 
  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). 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., "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick, Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30 held at the University of Toronto 20-24 June, 1966, Academic Press, London, p. 57, Bibcode:1967IAUS...30...57E 
  6. ^ 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 
  7. ^ a b Kaler, James B., "Nihal", Stars, retrieved 2008-11-18 
  8. ^ Mallik, Sushma V. (December 1999), "Lithium abundance and mass", Astronomy and Astrophysics 352: 495–507, Bibcode:1999A&A...352..495M 
  9. ^ 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 
  10. ^ Bernacca, P. L.; Perinotto, M. (1970). "A catalogue of stellar rotational velocities". Contributi Osservatorio Astronomico di Padova in Asiago 239 (1). Bibcode:1970CoAsi.239....1B. 
  11. ^ Allen, Richard Hinckley (1899), Star-names and Their Meanings, New York: G. E. Steichert, pp. 265, 269 
  12. ^ Perryman, Michael (2010), The Making of History's Greatest Star Map, Heidelberg: Springer-Verlag, doi:10.1007/978-3-642-11602-5 
  13. ^ 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 
  14. ^ "NSV 2008, database entry", New Catalogue of Suspected Variable Stars, the improved version (Moscow, Russia.: Sternberg Astronomical Institute), retrieved 2008-11-18