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Beta Librae

October 21, 2023

Beta Librae (β Librae, abbreviated Beta Lib, β Lib), formally named Zubeneschamali /zuːˌbɛnɛʃəˈmeɪli/,[10][11] is (despite its 'beta' designation) the brightest star in the zodiac constellation of Libra. From parallax measurements, its distance can be estimated as 185 light-years (57 parsecs) from the Sun.[1]

Beta Librae
The position of β Librae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Libra
Right ascension 15h 17m 00.41382s[1]
Declination −09° 22′ 58.4919″[1]
Apparent magnitude (V) 2.61[2]
Characteristics
Spectral type B8 V[3]
U−B color index −0.359[4]
B−V color index −0.106[4]
Variable type Suspected
Astrometry
Radial velocity (Rv)−35.2[2] km/s
Proper motion (μ) RA: −98.10[1] mas/yr
Dec.: −19.65[1] mas/yr
Parallax (π)17.62 ± 0.16 mas[1]
Distance185 ± 2 ly
(56.8 ± 0.5 pc)
Absolute magnitude (MV)−1.16[5]
Details
Mass3.5+0.3
−0.2[3] M☉
Radius4.9[6] R☉
Luminosity130 L☉
Temperature12300[7] K
Metallicity [Fe/H]0.33[3] dex
Rotational velocity (v sin i)250[8] km/s
Age80+50
−40[3] Myr
Other designations
Zubeneschamali, Kiffa Australis, Lanx Borealis, β Lib, 27 Librae, BD-08° 3935, FK5 564, HD 135742, HIP 74785, HR 5685, NSV 7009, SAO 140430[9]
Database references
SIMBADdata

The apparent visual magnitude of this star is 2.6.[2] According to Eratosthenes, Beta Librae was observed to be brighter than Antares. Ptolemy, 350 years later, said it was as bright as Antares. The discrepancy may be due to Antares becoming brighter, but this is not known for certain. It could simply be caused by Beta Librae being a variable star, showing a present-day variability of 0.03 of a magnitude.[12]

Name Edit

β Librae (Latinised to Beta Librae) is the star's Bayer designation.

It bore the traditional name Zubeneschamali /ˌzuːbənˌɛʃəˈmeɪli/ (less common renderings, or corruptions, are Zuben Eschamali, Zuben el Chamali, Zubenesch, Zubenelg), derived from the Arabic الزُّبَانَى الشَمَالِي (al-zubānā al-šamāliyy) meaning "the northern claw". This name originated in a time when Libra was viewed as representing the "claws of the scorpion".[12] There was also Kiffa Borealis, from the Arabic al-kiffah aš-šamāliyy "the northern pan (of the scales)" and the Latin equivalent Lanx Borealis.[13] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[14] to catalogue and standardize proper names for stars. The WGSN approved the name Zubeneschamali for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.[11]

In Chinese, 氐宿 (Dī Xiù), meaning Root, refers to an asterism consisting of β Librae, α2 Librae, ι Librae and γ Librae.[15] Consequently, the Chinese name for β Librae itself is 氐宿四 (Dī Xiù sì), "the Fourth Star of Root".[16]

Properties Edit

Based upon the features of its spectrum, Beta Librae has a stellar classification of B8 V,[3] making it a B-type main-sequence star. It is about 130 times more luminous than the Sun and has a surface temperature of 12,300 K,[7] double that of the Sun. This high temperature produces light with a simple spectrum, making it ideal for examining the interstellar gas and dust between Earth and the star. Like many stars of its kind, it is spinning rapidly, over 100 times faster than the Sun with a projected rotational velocity of 250 km·s−1.[8] The measured angular diameter of the primary star is 0.801 mas.[7] At the estimated distance of this system, this yields a physical size of about 4.9 times the radius of the Sun.[6]

This type of massive, hydrogen-fusing star often appears blue-white, and is usually stated to be white or bluish by modern observers, but earlier observers often described Beta Librae as the only greenish star visible to the naked eye.[17] There seems to be no generally accepted explanation for why some observers see it as green.[18] The small periodic variations in the magnitude of Beta Librae suggest the presence of a companion star which is not directly observable from Earth.[19] However, it is categorized as a single star.[20]

See also Edit

References Edit

  1. ^ a b c d e f 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 c Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veröff. Astron. Rechen-Inst. Heidelb, Astronomisches Rechen-Institut Heidelberg, 35 (35): 1, Bibcode:1999VeARI..35....1W.
  3. ^ a b c d e Janson, Markus; et al. (August 2011), "High-contrast Imaging Search for Planets and Brown Dwarfs around the Most Massive Stars in the Solar Neighborhood", The Astrophysical Journal, 736 (2): 89, arXiv:1105.2577, Bibcode:2011ApJ...736...89J, doi:10.1088/0004-637X/736/2/89, S2CID 119217803
  4. ^ a b Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", Astrophysical Journal Supplement, 15: 459, Bibcode:1968ApJS...15..459G, doi:10.1086/190168
  5. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  6. ^ a b Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3 ed.), Birkhäuser, ISBN 3540296921. The radius (R*) is given by:
     
  7. ^ a b c Zorec, J.; et al. (July 2009), "Fundamental parameters of B supergiants from the BCD system. I. Calibration of the (λ_1, D) parameters into Teff", Astronomy and Astrophysics, 501 (1): 297–320, arXiv:0903.5134, Bibcode:2009A&A...501..297Z, doi:10.1051/0004-6361/200811147, S2CID 14969137
  8. ^ a b Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590
  9. ^ "bet Lib". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2007-01-22.
  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. ^ a b "IAU Catalog of Star Names". Retrieved 28 July 2016.
  12. ^ a b AAS (2006), (PDF), Auckland Astronomical Society, archived from the original (PDF) on 2012-02-12, retrieved 2009-01-25
  13. ^ La Hire, Philippe (1727), Tabulae Astronomicae, Parisiis : Apud Montalant, typographum & bibliopolam ..., see star table, page 13.
  14. ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 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 2008-10-25 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  17. ^ Kaler, James B. (2006), , Stars, University of Illinois, archived from the original on 2006-07-14, retrieved 2006-07-03
  18. ^ Burnham, Robert, Jr. (1978), Burnham's Celestial Handbook, vol. 2, New York: Dover Publications, p. 1105, ISBN 0-486-23568-8.{{citation}}: CS1 maint: multiple names: authors list (link)
  19. ^ Mark Fisher (1999–2006), "Zuben Elschemali", The Electronic Sky, retrieved 2009-01-25
  20. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.

External links Edit

  • Odeh, Moh'd (1998–2006), , Islamic Crescents' Observation Project, archived from the original on 2008-02-02, retrieved 2006-07-03 – Find more Arabic Star Names and their meanings.
  • Beta Librae on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

October 21, 2023
beta, librae, librae, abbreviated, beta, formally, named, zubeneschamali, despite, beta, designation, brightest, star, zodiac, constellation, libra, from, parallax, measurements, distance, estimated, light, years, parsecs, from, position, librae, circled, obse. Beta Librae b Librae abbreviated Beta Lib b Lib formally named Zubeneschamali z uː ˌ b ɛ n ɛ ʃ e ˈ m eɪ l i 10 11 is despite its beta designation the brightest star in the zodiac constellation of Libra From parallax measurements its distance can be estimated as 185 light years 57 parsecs from the Sun 1 Beta LibraeThe position of b Librae circled Observation dataEpoch J2000 Equinox J2000Constellation LibraRight ascension 15h 17m 00 41382s 1 Declination 09 22 58 4919 1 Apparent magnitude V 2 61 2 CharacteristicsSpectral type B8 V 3 U B color index 0 359 4 B V color index 0 106 4 Variable type SuspectedAstrometryRadial velocity Rv 35 2 2 km sProper motion m RA 98 10 1 mas yr Dec 19 65 1 mas yrParallax p 17 62 0 16 mas 1 Distance185 2 ly 56 8 0 5 pc Absolute magnitude MV 1 16 5 DetailsMass3 5 0 3 0 2 3 M Radius4 9 6 R Luminosity130 L Temperature12300 7 KMetallicity Fe H 0 33 3 dexRotational velocity v sin i 250 8 km sAge80 50 40 3 MyrOther designationsZubeneschamali Kiffa Australis Lanx Borealis b Lib 27 Librae BD 08 3935 FK5 564 HD 135742 HIP 74785 HR 5685 NSV 7009 SAO 140430 9 Database referencesSIMBADdataThe apparent visual magnitude of this star is 2 6 2 According to Eratosthenes Beta Librae was observed to be brighter than Antares Ptolemy 350 years later said it was as bright as Antares The discrepancy may be due to Antares becoming brighter but this is not known for certain It could simply be caused by Beta Librae being a variable star showing a present day variability of 0 03 of a magnitude 12 Contents 1 Name 2 Properties 3 See also 4 References 5 External linksName Editb Librae Latinised to Beta Librae is the star s Bayer designation It bore the traditional name Zubeneschamali ˌ z uː b en ˌ ɛ ʃ e ˈ m eɪ l i less common renderings or corruptions are Zuben Eschamali Zuben el Chamali Zubenesch Zubenelg derived from the Arabic الز ب ان ى الش م ال ي al zubana al samaliyy meaning the northern claw This name originated in a time when Libra was viewed as representing the claws of the scorpion 12 There was also Kiffa Borealis from the Arabic al kiffah as samaliyy the northern pan of the scales and the Latin equivalent Lanx Borealis 13 In 2016 the International Astronomical Union organized a Working Group on Star Names WGSN 14 to catalogue and standardize proper names for stars The WGSN approved the name Zubeneschamali for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names 11 In Chinese 氐宿 Di Xiu meaning Root refers to an asterism consisting of b Librae a2 Librae i Librae and g Librae 15 Consequently the Chinese name for b Librae itself is 氐宿四 Di Xiu si the Fourth Star of Root 16 Properties EditBased upon the features of its spectrum Beta Librae has a stellar classification of B8 V 3 making it a B type main sequence star It is about 130 times more luminous than the Sun and has a surface temperature of 12 300 K 7 double that of the Sun This high temperature produces light with a simple spectrum making it ideal for examining the interstellar gas and dust between Earth and the star Like many stars of its kind it is spinning rapidly over 100 times faster than the Sun with a projected rotational velocity of 250 km s 1 8 The measured angular diameter of the primary star is 0 801 mas 7 At the estimated distance of this system this yields a physical size of about 4 9 times the radius of the Sun 6 This type of massive hydrogen fusing star often appears blue white and is usually stated to be white or bluish by modern observers but earlier observers often described Beta Librae as the only greenish star visible to the naked eye 17 There seems to be no generally accepted explanation for why some observers see it as green 18 The small periodic variations in the magnitude of Beta Librae suggest the presence of a companion star which is not directly observable from Earth 19 However it is categorized as a single star 20 See also EditList of stars in Libra Alpha Librae Zubenelgenubi References Edit a b c d e f van Leeuwen F November 2007 Validation of the new Hipparcos reduction Astronomy and Astrophysics 474 2 653 664 arXiv 0708 1752 Bibcode 2007A amp A 474 653V doi 10 1051 0004 6361 20078357 S2CID 18759600 a b c Wielen R et al 1999 Sixth Catalogue of Fundamental Stars FK6 Part I Basic fundamental stars with direct solutions Veroff Astron Rechen Inst Heidelb Astronomisches Rechen Institut Heidelberg 35 35 1 Bibcode 1999VeARI 35 1W a b c d e Janson Markus et al August 2011 High contrast Imaging Search for Planets and Brown Dwarfs around the Most Massive Stars in the Solar Neighborhood The Astrophysical Journal 736 2 89 arXiv 1105 2577 Bibcode 2011ApJ 736 89J doi 10 1088 0004 637X 736 2 89 S2CID 119217803 a b Gutierrez Moreno Adelina Moreno Hugo June 1968 A photometric investigation of the Scorpio Centaurus association Astrophysical Journal Supplement 15 459 Bibcode 1968ApJS 15 459G doi 10 1086 190168 Anderson E Francis Ch 2012 XHIP An extended hipparcos compilation Astronomy Letters 38 5 331 arXiv 1108 4971 Bibcode 2012AstL 38 331A doi 10 1134 S1063773712050015 S2CID 119257644 a b Lang Kenneth R 2006 Astrophysical formulae Astronomy and astrophysics library vol 1 3 ed Birkhauser ISBN 3540296921 The radius R is given by 2 R 56 8 0 801 10 3 AU 0 0046491 AU R 9 8 R displaystyle begin aligned 2 cdot R amp frac 56 8 cdot 0 801 cdot 10 3 text AU 0 0046491 text AU R bigodot amp approx 9 8 cdot R bigodot end aligned nbsp a b c Zorec J et al July 2009 Fundamental parameters of B supergiants from the BCD system I Calibration of the l 1 D parameters into Teff Astronomy and Astrophysics 501 1 297 320 arXiv 0903 5134 Bibcode 2009A amp A 501 297Z doi 10 1051 0004 6361 200811147 S2CID 14969137 a b Abt Helmut A Levato Hugo Grosso Monica July 2002 Rotational Velocities of B Stars The Astrophysical Journal 573 1 359 365 Bibcode 2002ApJ 573 359A doi 10 1086 340590 bet Lib SIMBAD Centre de donnees astronomiques de Strasbourg Retrieved 2007 01 22 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 a b IAU Catalog of Star Names Retrieved 28 July 2016 a b AAS 2006 LIBRA A Balanced View page 7 of PDF PDF Auckland Astronomical Society archived from the original PDF on 2012 02 12 retrieved 2009 01 25 La Hire Philippe 1727 Tabulae Astronomicae Parisiis Apud Montalant typographum amp bibliopolam see star table page 13 IAU Working Group on Star Names WGSN International Astronomical Union retrieved 22 May 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 Kaler James B 2006 Zubeneschamali Stars University of Illinois archived from the original on 2006 07 14 retrieved 2006 07 03 Burnham Robert Jr 1978 Burnham s Celestial Handbook vol 2 New York Dover Publications p 1105 ISBN 0 486 23568 8 a href Template Citation html title Template Citation citation a CS1 maint multiple names authors list link Mark Fisher 1999 2006 Zuben Elschemali The Electronic Sky retrieved 2009 01 25 Eggleton P P Tokovinin A A September 2008 A catalogue of multiplicity among bright stellar systems Monthly Notices of the Royal Astronomical Society 389 2 869 879 arXiv 0806 2878 Bibcode 2008MNRAS 389 869E doi 10 1111 j 1365 2966 2008 13596 x S2CID 14878976 External links EditOdeh Moh d 1998 2006 Arabic Star Names Islamic Crescents Observation Project archived from the original on 2008 02 02 retrieved 2006 07 03 Find more Arabic Star Names and their meanings Beta Librae on WikiSky DSS2 SDSS GALEX IRAS Hydrogen a X Ray Astrophoto Sky Map Articles and images Retrieved from https en wikipedia org w index php title Beta Librae amp oldid 1170134780, wikipedia, wiki, book, books, library,

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