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Alpha Leporis

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α Leporis
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
Evolutionary stage Blue loop (yellow supergiant)[3]
Spectral type F0 Ib[4]
U−B color index +0.386[2]
B−V color index +0.2[5]
Astrometry
Radial velocity (Rv)+23.9[6] km/s
Proper motion (μ) RA: +3.56[1] mas/yr
Dec.: +1.18[1] mas/yr
Parallax (π)1.47 ± 0.14 mas[1]
Distance2,200 ± 200 ly
(680 ± 60 pc)[1]
Absolute magnitude (MV)-5.7[7]
Details
Mass13.9±0.8[8] M☉
Radius129[9] R☉
Luminosity30,502±3,111[10] L☉
Surface gravity (log g)1.34±0.07[8] cgs
Temperature7,253 or 7,290[11] K
Metallicity [Fe/H]+0.01–0.06[11] dex
Rotational velocity (v sin i)13–21[5] km/s
Age13[8] 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/,[12][13] is the brightest star in the constellation of Lepus.

Nomenclature

[edit]

Alpha Leporis is the star's Bayer designation. The traditional name Arneb comes from the Arabic أرنب ’arnab 'hare'[14] ('Lepus' is Latin for hare). 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 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.[17] Consequently, the Chinese name for α Leporis itself is 廁一 (Cè yī), "the First Star of Toilet".[18]

Properties

[edit]

This is a massive star with about 14 times the mass of the Sun.[8] The interferometer-measured angular diameter of this star, after correction for limb darkening, is 1.77 ± 0.09 mas.[19] 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.[9] Alpha Leporis has a stellar classification of F0 Ib,[4] with the Ib luminosity class indicating that it is a lower luminosity yellow supergiant star. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[20] The effective temperature of the outer envelope is about 7,300 K,[11] which gives the star a yellowish-white hue that is typical of F-type stars.[21] It is an estimated 13 million years old.[8]

Arneb is an older, dying star that has already passed through a red supergiant phase and is now contracting and heating up in the latter phases of stellar evolution, in a blue loop.[3]

Namesakes

[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. S2CID 18759600.
  2. ^ a b Gutierrez-Moreno, Adelina; et al. (1966), "A System of photometric standards", Publications of the Department of Astronomy University of Chile, 1, Publicaciones Universidad de Chile, Department de Astronomy: 1–17, Bibcode:1966PDAUC...1....1G
  3. ^ a b Smiljanic, R.; Barbuy, B.; De Medeiros, J. R.; Maeder, A. (April 2006), "CNO in evolved intermediate mass stars", Astronomy & Astrophysics, 449 (2): 655–671, arXiv:astro-ph/0511329, Bibcode:2006A&A...449..655S, doi:10.1051/0004-6361:20054377, ISSN 0004-6361
  4. ^ 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
  5. ^ a b Ayres, Thomas R. (February 20, 2018). "Cracking the Conundrum of F-Supergiant Coronae". The Astrophysical Journal. 854 (2): 95. arXiv:1802.02552. Bibcode:2018ApJ...854...95A. doi:10.3847/1538-4357/aaa6d7. ISSN 0004-637X.
  6. ^ Evans, D. S. (June 20–24, 1966), "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, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E
  7. ^ Giridhar, S.; Goswami, A.; Kunder, A.; Muneer, S.; Selvakumar, G. (August 1, 2013). "Identification of metal-poor stars using the artificial neural network". Astronomy and Astrophysics. 556: A121. arXiv:1307.6308. Bibcode:2013A&A...556A.121G. doi:10.1051/0004-6361/201219918. ISSN 0004-6361. Alpha Leporis' database entry at VizieR.
  8. ^ 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.
  9. ^ a b Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
  10. ^ McDonald, I.; Zijlstra, A. A.; Watson, R. A. (October 1, 2017), "Fundamental parameters and infrared excesses of Tycho-Gaia stars", Monthly Notices of the Royal Astronomical Society, 471 (1): 770–791, arXiv:1706.02208, doi:10.1093/mnras/stx1433, ISSN 0035-8711 Arneb's database entry at VizieR.
  11. ^ a b c Luck, R. Earle (2014). "Parameters and Abundances in Luminous Stars". The Astronomical Journal. 147 (6): 137. Bibcode:2014AJ....147..137L. doi:10.1088/0004-6256/147/6/137. Alpha Leporis' database entry at VizieR.
  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 July 28, 2016.
  14. ^ Allen, Richard Hinckley (1899), Star-names and Their Meanings, G. E. Stechert, p. 268
  15. ^ "IAU Working Group on Star Names (WGSN)". Retrieved May 22, 2016.
  16. ^ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved July 28, 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. ^ Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039
  20. ^ 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, archived from the original on June 25, 2019, retrieved February 4, 2012
  21. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on December 3, 2013, retrieved January 16, 2012
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