Alpha Lupi

Alpha Lupi (α Lupi, α Lup) is the brightest star in the southern constellation of Lupus. According to the Bortle Dark-Sky Scale, its apparent visual magnitude of 2.3[2] makes it readily visible to the naked eye even from highly light-polluted locales. Based upon parallax measurements made during the Hipparcos mission,[11] the star is around 460 light-years (140 parsecs) from the solar system.[1] It is one of the nearest soon supernova (explosion) candidates,[12] and is the brightest star without a pre-Bayer designation western classical/arabic world name, ranking 75 places below the sun.

Alpha Lupi
Location of α Lupi (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Lupus
Right ascension  14h 41m 55.75579s[1]
Declination –47° 23′ 17.5155″[1]
Apparent magnitude (V) 2.30[2] (2.29 - 2.34[3])
Characteristics
Spectral type B1.5 III[4]
U−B color index –0.88[2]
B−V color index –0.20[2]
Variable type β Cep[3]
Astrometry
Radial velocity (Rv)+5.4 ± 0.6[5] km/s
Proper motion (μ) RA: −20.94[1] mas/yr
Dec.: −23.67[1] mas/yr
Parallax (π)7.02 ± 0.17[1] mas
Distance460 ± 10 ly
(142 ± 3 pc)
Absolute magnitude (MV)−4.3[6]
Details
Mass10.1 ± 1.0[7] M☉
Luminosity25,000[6] L☉
Surface gravity (log g)3.46[6] cgs
Temperature21,820 ± 2,160[8] K
Metallicity [Fe/H]0.04[9] dex
Rotational velocity (v sin i)16[5] km/s
Age16–20[5] Myr
Other designations
CD-46° 9501, FK5 541, HD 129056, HIP 71860, HR 5469, SAO 225128.[10]
Database references
SIMBADdata

Characteristics

Alpha Lupi is a giant star with a stellar classification of B1.5 III.[4] It has about ten times the mass of the sun (~10 M☉)[7] yet is radiating 25,000[6] times the Sun's luminosity. The outer atmosphere has an effective temperature of 21,820 K,[8] which gives it the blue-white glow of a B-type star. In 1956 it was identified as a Beta Cephei variable by Bernard Pagel and colleagues,[13] which means it undergoes periodic changes in luminosity because of pulsations in the atmosphere. The variability period is 0.29585 days,[9] or just over 7 hours, 6 minutes. The magnitude varies by about 0.05, or about 5% of the total luminosity. A 14th magnitude star situated 26" from Alpha Lupi is listed as a companion in double star catalogues.[14]

This star is a proper motion member of the Upper-Centaurus Lupus sub-group in the Scorpius-Centaurus OB association, the nearest such co-moving association of massive stars to the Sun.[6] This is a gravitationally unbound stellar association with an estimated age of 16–20 million years. The association is also the source of a bubble of hot gas that contains the Sun, known as the Local Bubble.[5]

Regions from which visible

Apart from the Southern Hemisphere for much of the year, it can be viewed for a shorter season from the northern tropics and from parts of the northern subtropical latitudes; it lies beyond much of the rest of its asterism, in turn south of Libra.

Etymology

In Chinese, Kekouan 騎官 (Qí Guān), meaning Imperial Guards, refers to an asterism consisting of α Lupi, γ Lupi, δ Lupi, κ Centauri, β Lupi, λ Lupi, ε Lupi, μ Lup, π Lupi, and ο Lupi .[15] Consequently, the Chinese name for α Lupi itself is 騎官十 (Qí Guān shí, English: the Tenth Star of Imperial Guards.).[16]

R. H. Allen described this star as having the Chinese name Yang Mun or Men（南門), meaning "the South Gate", in his work Star-Names and their Meanings.[17] In Chinese astronomy, 南門 is located in Horn mansion and consisted of α and ε Centauri. Yang Mun was translated in Pinyin as 陽門, meaning "the Yang Gate", and refers to the asterism in Neck mansion, containing stars from the modern constellation Centaurus.[18] Allen also suggested that the Babylonian name for the star was "Kakkab Su-gub Gud-Elim" (Star Left Hand of the Horned Bull).[17]

gollark: https://www.reddit.com/r/AV1/comments/hb039t/8mib_shrek_is_back/Insanity but also very cool.
gollark: I read that it couldn't actually be unambiguously parsed because parsing some construct required solving the halting problem because the syntax is different depending on some information or other only available at runtime.
gollark: You can lose your sanity through the regexes *and* any other part of the language!
gollark: Only if you don't value your sanity.
gollark: Does exact matching actually work on sound files? It's possible there's some weird conversion stuff going on, and if they're from a lossily compressed source it probably won't work exactly right.

See also
  • Traditional Chinese star names
    • Centaurus
    • Lupus

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.
  2. Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J
  3. Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007–2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: 02025. Bibcode:2009yCat....102025S.
  4. Hiltner, W. A.; Garrison, R. F.; Schild, R. E. (July 1969), "MK Spectral Types for Bright Southern OB Stars", Astrophysical Journal, 157: 313–326, Bibcode:1969ApJ...157..313H, doi:10.1086/150069
  5. Jilinski, E.; et al. (March 2006), "Radial velocity measurements of B stars in the Scorpius-Centaurus association", Astronomy and Astrophysics, 448 (3): 1001–1006, arXiv:astro-ph/0601643, Bibcode:2006A&A...448.1001J, doi:10.1051/0004-6361:20041614
  6. de Geus, E. J.; de Zeeuw, P. T.; Lub, J. (June 1989), "Physical parameters of stars in the Scorpio-Centaurus OB association", Astronomy and Astrophysics, 216 (1–2): 44–61, Bibcode:1989A&A...216...44D
  7. Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 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
  8. Sokolov, N. A. (May 1995), "The determination of T_eff_ of B, A and F main sequence stars from the continuum between 3200 A and 3600 A", Astronomy and Astrophysics Supplement, 110: 553–564, Bibcode:1995A&AS..110..553S
  9. Daszyńska-Daszkiewicz, J.; Niemczura, E. (April 2005), "Metallicity of mono- and multiperiodic β Cephei stars", Astronomy and Astrophysics, 433 (3): 1031–1035, arXiv:astro-ph/0410442, Bibcode:2005A&A...433.1031D, doi:10.1051/0004-6361:20040397
  10. "V* alf Lup -- Variable Star of beta Cep type", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2009-10-26
  11. Perryman, M. A. C.; et al. (April 1997), "The HIPPARCOS Catalogue", Astronomy & Astrophysics, 323: L49–L52, Bibcode:1997A&A...323L..49P
  12. Firestone, R. B. (July 2014), "Observation of 23 Supernovae That Exploded <300 pc from Earth during the past 300 kyr" (PDF), The Astrophysical Journal, 789 (1): 11, Bibcode:2014ApJ...789...29F, doi:10.1088/0004-637X/789/1/29, 29.
  13. Pagel, B. E. J. (1956), "Results of a search for bright β Cephei variables in the southern sky", Monthly Notices of the Royal Astronomical Society, 116: 10–24, Bibcode:1956MNRAS.116...10P, doi:10.1093/mnras/116.1.10
  14. Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
  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 Archived 2011-01-30 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.]
  17. Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York, NY: Dover Publications Inc. p. 279. ISBN 0-486-21079-0.
  18. Allen transliterated 南門 as Nan Mun in Centaurus.
    Allen, R. H. (1963). Star Names: Their Lore and Meaning. p. 153.
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