Alpha Leporis (α Leporis, abbreviated Alpha Lep, α Lep), formally named Arneb /ˈɑːrnɛb/,[11][12] is the brightest star in the constellation of Lepus.
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 | 6,850±80[8] K |
Metallicity [Fe/H] | +0.01[7] dex |
Rotational velocity (v sin i) | 13–21[5] km/s |
Age | 13[8] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Nomenclature
editAlpha Leporis is the star's Bayer designation. The traditional name Arneb comes from the Arabic أرنب ’arnab 'hare'[13] ('Lepus' is Latin for hare). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[14] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[15] 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.[16] Consequently, the Chinese name for α Leporis itself is 廁一 (Cè yī), "the First Star of Toilet".[17]
Properties
editThis is a massive star with about 12 times the mass of the Sun.[18] 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 6,850–7,500 K, which gives the star a yellow-white hue that is typical of F-type stars.[21] It is an estimated 17.5 million years old.[18]
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] 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. [22]
Namesakes
editUSS Arneb (AKA-56) was a ship of the United States Navy.
References
edit- ^ 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.
- ^ 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
- ^ 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
- ^ 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
- ^ 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.
- ^ 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
- ^ a b 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.
- ^ a b c d 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.
- ^ 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:
- ^ 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.
- ^ 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.
- ^ "IAU Catalog of Star Names". Retrieved July 28, 2016.
- ^ Allen, Richard Hinckley (1899), Star-names and Their Meanings, G. E. Stechert, p. 268
- ^ "IAU Working Group on Star Names (WGSN)". Retrieved May 22, 2016.
- ^ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved July 28, 2016.
- ^ (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.
- ^ (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.
- ^ a b Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 1, 2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. ISSN 0035-8711. Alpha Leporis' database entry at VizieR.
- ^ 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
- ^ 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
- ^ Soubiran, Caroline; Le Campion, Jean-François; Brouillet, Nathalie; Chemin, Laurent (June 1, 2016). "The PASTEL catalogue: 2016 version". Astronomy and Astrophysics. 591: A118. arXiv:1605.07384. Bibcode:2016A&A...591A.118S. doi:10.1051/0004-6361/201628497. ISSN 0004-6361. here Alpha Leporis' database entry at VizieR.
- ^ Kaler, James B., "ARNEB (Alpha Leporis)", Stars, University of Illinois, retrieved January 8, 2012