Zubeneschamali

Zubeneschamali
	Zubeneschamali se ligging (in die rooi sirkel).
Sterrebeeld	Weegskaal
Bayer-naam	Beta Librae
Spektraaltipe	B8 V
Soort	Hoofreeksster
	Waarnemingsdata (Epog J2000)
Regte klimming	15h 17m 00.41382s
Deklinasie	-09° 22′ 58.4919″
Skynmagnitude (m)	2,61
B-V-kleurindeks	-0,106
U-B-kleurindeks	-0,359
	Besonderhede
Massa (M☉)	3,5+0,3−0,2
Radius (R☉)	4,9
Ligsterkte (L☉)	130
Temperatuur (K)	12 300
Rotasiespoed (km/s)	250
Metaalinhoud [Fe/H]	0,33
	Eienskappe
Ouderdom (jaar)	80 miljoen
Veranderlikheid	Vermoed
	Ander name
	Zubeneschamali, Lanx Borealis, 27 Librae, BD-08° 3935, FK5 564, HD 135742, HIP 74785, HR 5685, NSV 7009, SAO 140430
Portaal	Sterrekunde

Zubeneschamali (ook bekend as Beta Librae of β Lib) is ondanks die Bayer-aanwysing "beta" die helderste ster in die sterrebeeld Weegskaal (Libra). Volgens parallaksmetings is dit sowat 185 ligjare van die Son af.^[2]

Eienskappe

Die ster se skynbare magnitude is 2,6.^[3] Volgens Eratosthenes van Sirene (276 tot 273 v.C.) was Zubeneschamali helderder as Antares (Alpha Scorpii). Ptolemeus het 350 jaar later gesê dit was net so helder soos Antares. Dié afwyking kan wees omdat Antares helderder geword het, maar dit is nie seker nie. Dit kon ook veroorsaak gewees het deurdat Zubeneschamali ’n veranderlike ster is, met ’n hedendaagse veranderlikheid van 0,03 magnitude.^[9]

Volgens die eienskappe van sy spektrum het Zubeneschamali ’n sterreklassifikasie van B8 V,^[1] wat dit ’n B-tipe hoofreeksster maak. Dit is sowat 130 keer helderder as die Son en het ’n effektiewe temperatuur van 12 300 K,^[6] dubbel die Son s'n. Dié hoë temperatuur produseer lig met ’n eenvoudige spektrum en maak dit ideaal om die interstellêre gas en stof tussen die Aarde en die ster te ondersoek. Soos baie sterre van sy soort roteer Zubeneschamali baie vinnig, meer as 100 keer so vinnig as die Son, teen sowat 250 km•s⁻¹.^[7] Sy radius is sowat 4,9 keer dié van die Son.^[5] Hierdie soort swaar ster wat waterstoffusie ondergaan, lyk dikwels blouwit en moderne waarnemers sien dit óf as blou óf as wit, maar vroeëre waarnemers het Zubeneschamali dikwels beskryf as die enigste ster wat met die blote oog groen lyk.^[10] Daar is geen aanvaarbare verduideliking vir waarom dit vir sommige waarnemers groen lyk nie.

Die klein periodieke wisseling in die helderheid van Zubeneschamali dui op die moontlike teenwoordigheid van ’n metgesel-ster wat nie regstreeks van die Aarde af gesien kan word nie.^[11] Dit word egter as ’n enkelster geklassifiseer.^[12]

Name

Die ster se Bayer-naam is "Beta Librae" en sy Flamsteed-naam "27 Librae". Die tradisionele naam is "Zubeneschamali", soms gespel Zuben Eschamali, Zuben el Chamali, Zubenesch of Zubenelg. Dit kom van die Arabiese ّالزُبَانَى الشَمَالِي al-zubānā al-šamāliyy, "die noordelike klou", uit die dae toe die Weegskaal beskou is as die kloue van die Skerpioen.^[9]

In 2016 het die Internasionale Astronomiese Unie se sternaamwerkgroep (WGSN) die naam "Zubeneschamali" vir die ster goedgekeur.^[13]

Verwysings

↑ ^1,0 ^1,1 ^1,2 ^1,3 ^1,4 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, doi:10.1088/0004-637X/736/2/89, Bibcode: 2011ApJ...736...89J
↑ ^2,0 ^2,1 ^2,2 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.
↑ ^3,0 ^3,1 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.
↑ ^4,0 ^4,1 Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", Astrophysical Journal Supplement 15: 459, doi:10.1086/190168, Bibcode: 1968ApJS...15..459G
↑ ^5,0 ^5,1 Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3 ed.), Birkhäuser, ISBN 3-540-29692-1, https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41 . Die radius (R_*) word aangedui deur:
${\begin{aligned}2\cdot R_{*}&={\frac {(56.8\cdot 0.801\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 9.8\cdot R_{\bigodot }\end{aligned}}$
↑ ^6,0 ^6,1 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, doi:10.1051/0004-6361/200811147, Bibcode: 2009A&A...501..297Z
↑ ^7,0 ^7,1 Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal 573 (1): 359–365, doi:10.1086/340590, Bibcode: 2002ApJ...573..359A
↑ "HD 135742 -- Variable Star", SIMBAD Astronomical Object Database, http://simbad.u-strasbg.fr/sim-id.pl?protocol=html&Ident=beta+librae, besoek op 2007-01-22
↑ ^9,0 ^9,1 AAS (2006), "LIBRA – A Balanced View (page 7 of PDF)", Auckland Astronomical Society, archived from the original on 2012-04-07, https://www.webcitation.org/66jjPrUOb?url=http://www.astronomy.org.nz/Documents/Journal/journal_200606.pdf, besoek op 2009-01-25
↑ Kaler, James B. (2006), "Zubeneschamali", Stars (University of Illinois), archived from the original on 2006-07-14, https://web.archive.org/web/20060714121424/http://www.astro.uiuc.edu/~kaler/sow/zubenes.html, besoek op 2006-07-03
↑ Mark Fisher (1999–2006), "Zuben Elschemali", The Electronic Sky, http://www.glyphweb.com/esky/stars/zubenelschemali.html, besoek op 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.
↑ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Besoek op 28 Julie 2016.

Eksterne skakels

Zubeneschamali op WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Artikels en foto's
Hierdie artikel is vertaal uit die Engelse Wikipedia

[apj736_2_89-1] 1,0 ^1,1 ^1,2 ^1,3 ^1,4 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, doi:10.1088/0004-637X/736/2/89, Bibcode: 2011ApJ...736...89J

[aaa474_2_653-2] 2,0 ^2,1 ^2,2 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.

[scfs-3] 3,0 ^3,1 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.

[apjs15_459-4] 4,0 ^4,1 Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", Astrophysical Journal Supplement 15: 459, doi:10.1086/190168, Bibcode: 1968ApJS...15..459G

[lang2006-5] 5,0 ^5,1 Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3 ed.), Birkhäuser, ISBN 3-540-29692-1, https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41 . Die radius (R_*) word aangedui deur:
${\begin{aligned}2\cdot R_{*}&={\frac {(56.8\cdot 0.801\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 9.8\cdot R_{\bigodot }\end{aligned}}$

[aaa501_1_297-6] 6,0 ^6,1 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, doi:10.1051/0004-6361/200811147, Bibcode: 2009A&A...501..297Z

[apj573_1_359-7] 7,0 ^7,1 Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal 573 (1): 359–365, doi:10.1086/340590, Bibcode: 2002ApJ...573..359A

[SIMBAD-8] "HD 135742 -- Variable Star", SIMBAD Astronomical Object Database, http://simbad.u-strasbg.fr/sim-id.pl?protocol=html&Ident=beta+librae, besoek op 2007-01-22

[Auk-9] 9,0 ^9,1 AAS (2006), "LIBRA – A Balanced View (page 7 of PDF)", Auckland Astronomical Society, archived from the original on 2012-04-07, https://www.webcitation.org/66jjPrUOb?url=http://www.astronomy.org.nz/Documents/Journal/journal_200606.pdf, besoek op 2009-01-25

[uiuc-10] Kaler, James B. (2006), "Zubeneschamali", Stars (University of Illinois), archived from the original on 2006-07-14, https://web.archive.org/web/20060714121424/http://www.astro.uiuc.edu/~kaler/sow/zubenes.html, besoek op 2006-07-03

[glyphweb-11] Mark Fisher (1999–2006), "Zuben Elschemali", The Electronic Sky, http://www.glyphweb.com/esky/stars/zubenelschemali.html, besoek op 2009-01-25

[mnras389_2_869-12] 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.

[WGSN1-13] "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Besoek op 28 Julie 2016.

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