Alpha Leporis

Alpha Leporis (α Leporis, abbreviated Alpha Lep, α Lep), formally named Arneb /ˈɑːrnɛb/,^[12][13] is the brightest star in the constellation of Lepus.

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]
Distance	2,200 ± 200 ly (680 ± 60 pc)[1]
Absolute magnitude (MV)	-5.7[7]
Details
Mass	13.9±0.8[8] M☉
Radius	129[9] R☉
Luminosity	30,502±3,111[10] L☉
Surface gravity (log g)	1.34±0.07[8] cgs
Temperature	7,253 or 7,290[11] K
Metallicity [Fe/H]	+0.01–0.06[11] dex
Rotational velocity (v sin i)	13–21[5] km/s
Age	13[8] Myr
Other designations
Arneb, 11 Leporis, BD−17°1166, FK5 207, HD 36673, HIP 25985, HR 1865, SAO 150547
Database references
SIMBAD	data

Nomenclature

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

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

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

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. 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. 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. 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. 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. 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. 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:

   ${\displaystyle {\begin{aligned}2\cdot R_{*}&={\frac {(10^{-3}\cdot 680\cdot 1.77)\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 259\cdot R_{\bigodot }\end{aligned}}}$

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. 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