Vega

	Vega
	Die ligging van Vega in die sterrebeeld Lier.
Sterrebeeld	Lier
Bayer-naam	α Lyrae
Spektraaltipe	A0V
Soort	Hoofreeksster
	Waarnemingsdata (Epog J2000)
Regte klimming	18h 36m 56,33635s
Deklinasie	+38° 47′ 01,2802″
Skynmagnitude (m)	0,03
	Besonderhede
Massa (M☉)	2,135
Radius (R☉)	2,362
Ligsterkte (L☉)	0,58
Ouderdom (jaar)	455 miljoen
Temperatuur (K)	9 602
Afstand (ligjaar)	25,04
	Ander name
	Lucida Lyrae, 3 Lyr, GJ 721, HR 7001, BD +38°3238, HD 172167, GCTP 4293.00, LTT 15486, SAO 67174, HIP 91262
Portaal	Sterrekunde

Vega is die helderste ster in die sterrebeeld Lier (Lyra) en die vyfde helderste ster in die lugruim. Dit is redelik naby: net 25 ligjare van die Aarde af. Sy Bayer-naam is Alpha Lyrae, afgekort as α Lyr.

Die ster is al deeglik deur sterrekundiges bestudeer en dit het daartoe gelei dat dit al "die belangrikste ster naas die Son" genoem is.^[2] Dit was omstreeks 12000 v.C. die noordelike poolster en sal dit omstreeks 13727 n.C. weer wees, wanneer sy deklinasie +86°14' sal wees.^[3] Vega was die eerste ster naas die Son wat gefotografeer is en die eerste waarvan die spektrum gemeet is. Dit was ook een van die eerste sterre waarvan die afstand gemeet is.

Eienskappe

Vega is net sowat ’n tiende so oud soos die Son, maar omdat dit 2,1 keer so groot is, is sy verwagte leeftyd ook net ’n tiende van die Son s’n. Albei sterre is tans naby die middel van hul leeftyd. Vega het ongewoon min elemente met ’n hoër atoomgetal as dié van helium.^[4] Daar word vermoed dit is ’n veranderlike ster waarvan die magnitude effens kan wissel.^[5] Dit draai vinnig teen ’n spoed van 274 km/s by sy ewenaar. Dit veroorsaak dat die ewenaar uitbult en daarom wissel die temperatuur van plek tot plek, met ’n maksimum by die pole. Van die Aarde af sien ’n mens Vega uit die rigting van een van sy pole.^[6]

Gebaseer op die groot mate van infrarooilig wat uitgestraal word, lyk dit of daar ’n stofskyf om die ster is. Dit is waarskynlik die gevolg van botsings tussen voorwerpe in ’n gordel om Vega wat ooreenstem met die Kuiper-gordel in die Sonnestelsel.^[7] Onreëlmatighede in die skyf dui ook op die moontlike teenwoordigheid van minstens een eksoplaneet, waarskynlik so groot soos Jupiter,^[8] wat om Vega wentel.^[9]

Name

Die ster se Bayer-naam is "Alpha Lyrae". Die eienaam, "Vega" (vroeër "Wega"),^[10] kom van die Arabiese wāqi‘, "vallende" of "landende" via die frase an-nasr al-wāqi‘, "die vallende arend".^[11] In 2016 het die Internasionale Astronomiese Unie se sternaamwerkgroep (WGSN) die naam "Vega" vir die ster goedgekeur.^[12]

Verwysings

↑ Kendall, E. Otis (1845), Uranography: Or, A Description of the Heavens; Designed for Academics and Schools; Accompanied by an Atlas of the Heavens, Philadelphia: Oxford University Press
↑ Gulliver, Austin F.; Hill, Graham; Adelman, Saul J. (1994), "Vega: A rapidly rotating pole-on star", The Astrophysical Journal 429 (2): L81–L84, doi:10.1086/187418, Bibcode: 1994ApJ...429L..81G
↑ Calculation by the Stellarium application version 0.10.2, http://www.stellarium.org, besoek op 2009-07-28
↑ Kinman, T.; Castelli, F. (2002), "The determination of T_eff for metal-poor A-type stars using V and 2MASS J, H and K magnitudes", Astronomy and Astrophysics 391 (3): 1039–1052, doi:10.1051/0004-6361:20020806, Bibcode: 2002A&A...391.1039K
↑ I.A., Vasil'yev et al. (1989-03-17), On the Variability of Vega, Commission 27 of the I.A.U, archived from the original on 2017-09-23, https://web.archive.org/web/20170923035950/http://www.konkoly.hu/pub/ibvs/3301/3308.txt, besoek op 2007-10-30
↑ Peterson, D. M. et al. (1999), "Vega is a rapidly rotating star", Nature 440 (7086): 896–899, doi:10.1038/nature04661, PMID 16612375, Bibcode: 2006Natur.440..896P
↑ Su, K. Y. L. et al. (2005), "The Vega Debris Disk: A Surprise from Spitzer", The Astrophysical Journal 628 (1): 487–500, doi:10.1086/430819, Bibcode: 2005ApJ...628..487S
↑ Wilner, D. et al. (2002), "Structure in the Dusty Debris around Vega", The Astrophysical Journal 569 (2): L115–L119, doi:10.1086/340691, Bibcode: 2002ApJ...569L.115W
↑ Wyatt, M. (2002), "Resonant Trapping of Planetesimals by Planet Migration: Debris Disk Clumps and Vega's Similarity to the Solar System", The Astrophysical Journal 598 (2): 1321–1340, doi:10.1086/379064, Bibcode: 2003ApJ...598.1321W
↑ Allen, Richard Hinckley (1963). Star Names: Their Lore and Meaning. Courier Dover Publications. ISBN 978-0-486-21079-7.
↑ Glassé, Cyril (2008). The new encyclopedia of Islam. Reference, Information and Interdisciplinary Subjects Series (3de uitg.). Rowman & Littlefield. p. 75. ISBN 978-0-7425-6296-7.
↑ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Besoek op 28 Julie 2016.

Eksterne skakels

Hierdie artikel is vertaal uit die Engelse Wikipedia

[kendall1845-1] Kendall, E. Otis (1845), Uranography: Or, A Description of the Heavens; Designed for Academics and Schools; Accompanied by an Atlas of the Heavens, Philadelphia: Oxford University Press

[apj429_2_L81-2] Gulliver, Austin F.; Hill, Graham; Adelman, Saul J. (1994), "Vega: A rapidly rotating pole-on star", The Astrophysical Journal 429 (2): L81–L84, doi:10.1086/187418, Bibcode: 1994ApJ...429L..81G

[stellarium-3] Calculation by the Stellarium application version 0.10.2, http://www.stellarium.org, besoek op 2009-07-28

[aaa391_3_1039-4] Kinman, T.; Castelli, F. (2002), "The determination of T_eff for metal-poor A-type stars using V and 2MASS J, H and K magnitudes", Astronomy and Astrophysics 391 (3): 1039–1052, doi:10.1051/0004-6361:20020806, Bibcode: 2002A&A...391.1039K

[merezhin-5] I.A., Vasil'yev et al. (1989-03-17), On the Variability of Vega, Commission 27 of the I.A.U, archived from the original on 2017-09-23, https://web.archive.org/web/20170923035950/http://www.konkoly.hu/pub/ibvs/3301/3308.txt, besoek op 2007-10-30

[nature440_7086_896-6] Peterson, D. M. et al. (1999), "Vega is a rapidly rotating star", Nature 440 (7086): 896–899, doi:10.1038/nature04661, PMID 16612375, Bibcode: 2006Natur.440..896P

[apj628_1_487-7] Su, K. Y. L. et al. (2005), "The Vega Debris Disk: A Surprise from Spitzer", The Astrophysical Journal 628 (1): 487–500, doi:10.1086/430819, Bibcode: 2005ApJ...628..487S

[apj569_2_L115-8] Wilner, D. et al. (2002), "Structure in the Dusty Debris around Vega", The Astrophysical Journal 569 (2): L115–L119, doi:10.1086/340691, Bibcode: 2002ApJ...569L.115W

[apj598_2_1321-9] Wyatt, M. (2002), "Resonant Trapping of Planetesimals by Planet Migration: Debris Disk Clumps and Vega's Similarity to the Solar System", The Astrophysical Journal 598 (2): 1321–1340, doi:10.1086/379064, Bibcode: 2003ApJ...598.1321W

[allen1963-10] Allen, Richard Hinckley (1963). Star Names: Their Lore and Meaning. Courier Dover Publications. ISBN 978-0-486-21079-7.

[glasse2008-11] Glassé, Cyril (2008). The new encyclopedia of Islam. Reference, Information and Interdisciplinary Subjects Series (3de uitg.). Rowman & Littlefield. p. 75. ISBN 978-0-7425-6296-7.

[WGSN1-12] "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Besoek op 28 Julie 2016.

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