Alpha Leporis

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Alpha Leporis
Diagram showing star positions and boundaries of the Lepus constellation and its surroundings
Cercle rouge 100%.svg

Location of α Leporis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Lepus
Right ascension 05h 32m 43.81612s[1]
Declination −17° 49′ 20.2414″[1]
Apparent magnitude (V) 2.589[2]
Characteristics
Spectral type F0 Ib[3]
U−B color index +0.386[2]
B−V color index +0.217[2]
Astrometry
Radial velocity (Rv) +23.9[4] km/s
Proper motion (μ) RA: +3.56[1] mas/yr
Dec.: +1.18[1] mas/yr
Parallax (π) 1.47 ± 0.14[1] mas
Distance 2,200 ± 200 ly
(680 ± 60 pc)
Absolute magnitude (MV) −6.574[1]
Details
Mass 13.9 ± 0.8[5] M
Radius 129[6] R
Luminosity 32,000[7] L
Surface gravity (log g) 1.34 ± 0.07[5] cgs
Temperature 6,850 ± 80[5] K
Metallicity [Fe/H] +0.04[8] dex
Rotational velocity (v sin i) 21[9] km/s
Age 13[5] Myr
Other designations
Arneb, 11 Leporis, BD −17°1166, FK5 207, HD 36673, HIP 25985, HR 1865, SAO 150547.

Alpha Leporis (α Lep, α Leporis) is the brightest star in the constellation Lepus. It has the traditional name Arneb, from the Arabic أرنب ’arnab "hare".[10]

This is a massive star with about 14 times the mass of the Sun.[5] The interferometer-measured angular diameter of this star, after correction for limb darkening, is 1.77 ± 0.09 mas.[11] At an estimated distance of 2,218 light-years (680 parsecs),[1] this yields a physical size of about 129 times the radius of the Sun.[6] Alpha Leporis has a stellar classification of F0 Ib,[3] with the Ib luminosity class indicating that it is a lower luminosity supergiant star. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[12] The effective temperature of the outer envelope is about 6,850 K,[5] which gives the star a yellow-white hue that is typical of F-type stars. It is an estimated 13 million years old.[5]

Alpha Leporis is an older, dying star that may have already passed through a supergiant phase and is now contracting and heating up in the latter phases of stellar evolution, or perhaps is still expanding into the supergiant phase. Based upon its estimated mass, it is expected to end its life in a spectacular stellar explosion known as a supernova.[13]

Arneb in Military[edit]

USS Arneb (AKA-56) was a ship of the United States navy.

References[edit]

  1. ^ a b c d e f g 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 Gutierrez-Moreno, Adelina et al. (1966), A System of photometric standards 1, Publicaciones Universidad de Chile, Department de Astronomy, pp. 1–17, Bibcode:1966PDAUC...1....1G 
  3. ^ a b Gray, R. O.; Napier, M. G.; Winkler, L. I. (April 2001), "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars", The Astronomical Journal 121 (4): 2148–2158, Bibcode:2001AJ....121.2148G, doi:10.1086/319956 
  4. ^ Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; John Frederick, Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E 
  5. ^ a b c d e f g 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. 
  6. ^ a b Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library 1 (3 ed.), Birkhäuser, ISBN 3-540-29692-1 . The radius (R*) is given by:
    \begin{align} 2\cdot R_*
 & = \frac{(10^{-3}\cdot 680\cdot 1.77)\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\
 & \approx 259\cdot R_{\bigodot}
\end{align}
  7. ^ Smiljanic, R. et al. (April 2006), "CNO in evolved intermediate mass stars", Astronomy and Astrophysics 449 (2): 655–671, arXiv:astro-ph/0511329, Bibcode:2006A&A...449..655S, doi:10.1051/0004-6361:20054377 
  8. ^ Venn, Kim A. (August 1995), "Atmospheric Parameters and LTE Abundances for 22 Galactic, A-Type Supergiants", Astrophysical Journal Supplement 99: 659, Bibcode:1995ApJS...99..659V, doi:10.1086/192201 
  9. ^ Royer, F. et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics 393: 897–911, arXiv:astro-ph/0205255, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943 
  10. ^ Allen, Richard Hinckley (1899), Star-names and Their Meanings, G. E. Stechert, p. 268 
  11. ^ Richichi; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics 431: 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039 
  12. ^ 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, retrieved 2012-02-04 
  13. ^ Kaler, James B., "ARNEB (Alpha Leporis)", Stars (University of Illinois), retrieved 2012-01-08