Astronomy:Alpha Leporis

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Short description: Brightest star in the constellation Lepus
α Leporis
Lepus constellation map.svg
Red circle.svg
Location of α Leporis (circled)
Observation data
Equinox J2000.0]] (ICRS)
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
Distance2,200 ± 200 ly
(680 ± 60 pc)
Absolute magnitude (MV)−6.574[1]
Details
Mass13.9 ± 0.8[5] M☉
Radius75[6] R☉
Luminosity12,023[7] L☉
Surface gravity (log g)1.34 ± 0.07[5] cgs
Temperature6,850 ± 80[5] K
Metallicity [Fe/H]+0.04[8] dex
Rotational velocity (v sin i)21[9] km/s
Age13[5] Myr
Other designations
Arneb, 11 Leporis, BD−17°1166, FK5 207, HD 36673, HIP 25985, HR 1865, SAO 150547
Database references
SIMBADdata

Alpha Leporis (α Leporis, abbreviated Alpha Lep, α Lep), formally named Arneb /ˈɑːrnɛb/,[10][11] is the brightest star in the constellation of Lepus.

Nomenclature

Alpha Leporis is the star's Bayer designation. The traditional name Arneb comes from the Arabic أرنب ’arnab 'hare'[12] ('Lepus' is Latin for hare). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[13] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[14] included a table of the first two batches of names approved by the WGSN; which included Arneb for this star.

In Chinese, 廁 (Cè), meaning Toilet, refers to an asterism consisting of α Leporis, β Leporis, γ Leporis and δ Leporis.[15] Consequently, the Chinese name for α Leporis itself is 廁一 (Cè yī), "the First Star of Toilet".[16]

Properties

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.[17] 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.[18] 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.[19] 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. However, this is not expected to happen for another million years. [6]

Arneb in Military

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

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 van Leeuwen, F. (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. 
  2. ↑ 2.0 2.1 2.2 Gutierrez-Moreno, Adelina et al. (1966), "A System of photometric standards", Publications of the Department of Astronomy University of Chile (Publicaciones Universidad de Chile, Department de Astronomy) 1: 1–17, Bibcode: 1966PDAUC...1....1G 
  3. ↑ 3.0 3.1 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, doi:10.1086/319956, Bibcode: 2001AJ....121.2148G 
  4. ↑ Evans, D. S. (June 20–24, 1966), "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, 30, University of Toronto: International Astronomical Union, p. 57, Bibcode: 1967IAUS...30...57E 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 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. doi:10.1111/j.1365-2966.2009.15979.x. Bibcode: 2010MNRAS.402.1369L. 
  6. ↑ 6.0 6.1 Kaler, James B., "ARNEB (Alpha Leporis)", Stars (University of Illinois), http://stars.astro.illinois.edu/sow/arneb.html, retrieved 2012-01-08 
  7. ↑ Smiljanic, R. et al. (April 2006), "CNO in evolved intermediate mass stars", Astronomy and Astrophysics 449 (2): 655–671, doi:10.1051/0004-6361:20054377, Bibcode: 2006A&A...449..655S 
  8. ↑ Venn, Kim A. (August 1995), "Atmospheric Parameters and LTE Abundances for 22 Galactic, A-Type Supergiants", Astrophysical Journal Supplement 99: 659, doi:10.1086/192201, Bibcode: 1995ApJS...99..659V 
  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, doi:10.1051/0004-6361:20020943, Bibcode: 2002A&A...393..897R 
  10. ↑ 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. 
  11. ↑ "IAU Catalog of Star Names". http://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt. Retrieved 28 July 2016. 
  12. ↑ Allen, Richard Hinckley (1899), Star-names and Their Meanings, G. E. Stechert, p. 268, https://books.google.com/books?id=5xQuAAAAIAAJ&pg=PA268 
  13. ↑ "IAU Working Group on Star Names (WGSN)". https://www.iau.org/science/scientific_bodies/working_groups/280/. Retrieved 22 May 2016. 
  14. ↑ "Bulletin of the IAU Working Group on Star Names, No. 1". http://www.pas.rochester.edu/~emamajek/WGSN/WGSN_bulletin1.pdf. Retrieved 28 July 2016. 
  15. ↑ (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.
  16. ↑ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 , Hong Kong Space Museum. Accessed on line November 23, 2010.
  17. ↑ Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics 431 (2): 773–777, doi:10.1051/0004-6361:20042039, Bibcode: 2005A&A...431..773R 
  18. ↑ Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1, https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41 . The radius (R*) is given by:
    [math]\displaystyle{ \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} }[/math]
  19. ↑ 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, http://www.astro.utoronto.ca/~garrison/mkstds.html, retrieved 2012-02-04 



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