Alnair

Alnair
	Alnair se ligging (in die rooi sirkel).
Sterrebeeld	Kraanvoël
Bayer-naam	Alpha Gruis
Spektraaltipe	B6 V
Soort	Hoofreeksster
	Waarnemingsdata (Epog J2000)
Regte klimming	22h 08m 13.98473s
Deklinasie	-46° 57′ 39.5078″
Skynmagnitude (m)	1,74
Absolute magnitude (M)	-0,72
B-V-kleurindeks	-0.13
U-B-kleurindeks	-0,47
	Besonderhede
Massa (M☉)	4
Radius (R☉)	3,4
Ligsterkte (L☉)	520
Ouderdom (jaar)	100 miljoen
Temperatuur (K)	13 920
Rotasiespoed (km/s)	215
Metaalinhoud [Fe/H]	-0,13 ± 0,02
	Ander name
	Al Na'ir, CD−47°14063, FK5 829, GCTP 5339.00, Gl 848.2, HD 209952, HIP 109268, HR 8425, SAO 230992
Portaal	Sterrekunde

Alnair (ook bekend as Alpha Gruis of α Gru) is ’n ster in die suidelike sterrebeeld Kraanvoël (Grus). Met ’n skynbare magnitude van 1,7 is dit die helderste ster in die sterrebeeld en een van die helderste sterre aan die naghemel. Dit is ’n B-tipe hoofreeksster sowat 101 ligjare van die Son af.

Naam

Die ster se Bayer-naam is "Alpha Gruis". Sy tradisionele naam is "Alnair" of "Al Nair" (soms "Al Na'ir" gespel),^[13] van die Arabiese al-nayyir, "die helder een", wat weer verkort is van sy Arabiese naam, al-nayyir min dhanab al-ḥūt (al-janūbiyy), "die helder een van die (suidelike) vis se stert".^[14] Op 21 Augustus 2016 het die Internasionale Astronomiese Unie se sternaamwerkgroep (WGSN)^[15] die amptelike naam Alnair aan die ster toegeken.^[16]

Alpha Gruis behoort saam met Beta Gruis, Delta Gruis, Theta Gruis, Iota Gruis en Lambda Gruis in die tradisionele Arabiese sterrekunde tot die sterrebeeld Suidelike Vis.^[17]

Eienskappe

Alnair het ’n sterreklassifikasie van B6 V,^[1] hoewel dit in sommige bronne aangegee word as B7 IV.^[18] Die eerste klassifikasie dui aan dit is ’n B-tipe hoofreeksster, wat waterstof in sy kern verbrand. Die ligsterkteklas IV van die tweede klassifikasie dui egter aan dat die ster ’n subreus is, wat beteken die vooraad waterstof in sy kern raak uitgeput en die ster begin weg van die hoofreeks af evolueer.

Alnair se radius is 3,4 sonradiusse.^[19] Dit roteer vinnig, teen sowat 215 km/s.^[10] Sy massa is omtrent 4 sonmassas en sy ligsterkte is sowat 520 keer dié van die Son.^[7] Sy oppervlaktemperatuur is 13 920 K^[9] en dit het sowat 74% van die metaalinhoud van die Son (elemente swaarder as waterstof en helium).^[11]

Volgens sy geraamde ouderdom en beweging kan dit lid van die AB Doradus-groep sterre wees wat saam deur die lug beweeg. Dié groep is sowat 70 miljoen jaar oud,^[20] wat ooreenstem met Alnair se geraamde ouderdom van 100 miljoen jaar.^[8]

Verwysings

↑ ^1,0 ^1,1 Gray, R. O.; et al. (Julie 2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637.
↑ ^2,0 ^2,1 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.
↑ ^3,0 ^3,1 ^3,2 Hoffleit, D.; Warren, W. H. jr. "HR 8425, databasis". The Bright Star Catalogue (5de hersiene uitg.). Centre de Données astronomiques de Strasbourg. Besoek op 5 September 2015.
↑ 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.
↑ Malagnini, M. L.; Morossi, C. (November 1990). "Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars". Astronomy and Astrophysics Supplement Series. 85 (3): 1015–1019. Bibcode:1990A&AS...85.1015M.
↑ Richichi, A.; Percheron, I.; Khristoforova, M. (Februarie 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.
↑ ^7,0 ^7,1 McCarthy, K.; White, R. J. (Junie 2012). "The Sizes of the Nearest Young Stars". The Astronomical Journal. 143 (6): 134. arXiv:1201.6600. Bibcode:2012AJ....143..134M. doi:10.1088/0004-6256/143/6/134.
↑ ^8,0 ^8,1 Su, K. Y. L.; et al. (Desember 2006). "Debris Disk Evolution around A Stars". The Astrophysical Journal. 653 (1): 675–689. arXiv:astro-ph/0608563. Bibcode:2006ApJ...653..675S. doi:10.1086/508649.
↑ ^9,0 ^9,1 Zorec, J.; et al. (Julie 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.
↑ ^10,0 ^10,1 Dachs, J.; et al. (Maart 1981). "Photoelectric scanner measurements of Balmer emission line profiles for southern Be stars. II - A survey for variations". Astronomy and Astrophysics Supplement Series. 43: 427–453. Bibcode:1981A&AS...43..427D.
↑ ^11,0 ^11,1 Niemczura, E. (Junie 2003). "Metallicities of the SPB stars from the IUE ultraviolet spectra". Astronomy and Astrophysics. 404 (2): 689–700. Bibcode:2003A&A...404..689N. doi:10.1051/0004-6361:20030546.. "The fractional abundance relative to the Sun is given by:
10^−0.13 = 0.74, or 74%."
↑ "LTT 8869 -- High proper-motion Star". SIMBAD (in Engels). Centre de Données astronomiques de Strasbourg. Geargiveer vanaf die oorspronklike op 16 Maart 2016. Besoek op 24 Desember 2011.
↑ Bowditch, LL.D., Nathaniel (2002) [1802]. "15: Navigational Astronomy" (PDF). The American Practical Navigator: An Epitome of Navigation. Bethesda, MD: National Imagery and Mapping Agency. p. 248. ISBN 978-0-939837-54-0. Geargiveer vanaf die oorspronklike (PDF) op 30 November 2016. Besoek op 20 September 2016.
↑ Kunitzsch, P.; Smart, T. (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd uitg.). Cambridge, Massachusetts: Sky Publishing. p. 39. ISBN 978-1-931559-44-7.
↑ Verwysingfout: Invalid <ref> tag; no text was provided for refs named WGSN
↑ "IAU Catalog of Star Names" (in Engels). Geargiveer vanaf die oorspronklike op 20 April 2020. Besoek op 28 Julie 2016.
↑ Allen, Richard H. (1963). Star Names: Their Lore and Meaning (herdruk uitg.). New York, NY: Dover Publications Inc. p. 237. ISBN 978-0-486-21079-7.
↑ 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.
↑ Lang, Kenneth R. (2006). Astrophysical formulae. Astronomy and astrophysics library. Vol. 1 (3rd uitg.). Birkhäuser. ISBN 978-3-540-29692-8.. "The radius (R_*) is given by:
${\begin{aligned}2\cdot R_{*}&={\frac {(10^{-3}\cdot 31\cdot 1.02)\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 6.8\cdot R_{\bigodot }\end{aligned}}$ "
↑ Zuckerman, B.; et al. (Mei 2011). "The Tucana/Horologium, Columba, AB Doradus, and Argus Associations: New Members and Dusty Debris Disks". The Astrophysical Journal. 732 (2): 61. arXiv:1104.0284. Bibcode:2011ApJ...732...61Z. doi:10.1088/0004-637X/732/2/61.

Verwysingfout: <ref> tag defined in <references> has no name attribute.

Eksterne skakels

Kaler, James B., "Al Nair (Alpha Gruis)", Stars (University of Illinois), http://stars.astro.illinois.edu/sow/alnair.html, besoek op 2011-12-26
Hierdie artikel is vertaal uit die Engelse Wikipedia

[aj132_1_161-1] 1,0 ^1,1 Gray, R. O.; et al. (Julie 2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637.

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

[bsc1-3] 3,0 ^3,1 ^3,2 Hoffleit, D.; Warren, W. H. jr. "HR 8425, databasis". The Bright Star Catalogue (5de hersiene uitg.). Centre de Données astronomiques de Strasbourg. Besoek op 5 September 2015.

[Anderson2012-4] 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.

[aass85_3_1015-5] Malagnini, M. L.; Morossi, C. (November 1990). "Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars". Astronomy and Astrophysics Supplement Series. 85 (3): 1015–1019. Bibcode:1990A&AS...85.1015M.

[aaa431_773-6] Richichi, A.; Percheron, I.; Khristoforova, M. (Februarie 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.

[aj143_6-7] 7,0 ^7,1 McCarthy, K.; White, R. J. (Junie 2012). "The Sizes of the Nearest Young Stars". The Astronomical Journal. 143 (6): 134. arXiv:1201.6600. Bibcode:2012AJ....143..134M. doi:10.1088/0004-6256/143/6/134.

[apj653_1_675-8] 8,0 ^8,1 Su, K. Y. L.; et al. (Desember 2006). "Debris Disk Evolution around A Stars". The Astrophysical Journal. 653 (1): 675–689. arXiv:astro-ph/0608563. Bibcode:2006ApJ...653..675S. doi:10.1086/508649.

[aaa501_1_297-9] 9,0 ^9,1 Zorec, J.; et al. (Julie 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.

[aaass43_427-10] 10,0 ^10,1 Dachs, J.; et al. (Maart 1981). "Photoelectric scanner measurements of Balmer emission line profiles for southern Be stars. II - A survey for variations". Astronomy and Astrophysics Supplement Series. 43: 427–453. Bibcode:1981A&AS...43..427D.

[aaa404_689-11] 11,0 ^11,1 Niemczura, E. (Junie 2003). "Metallicities of the SPB stars from the IUE ultraviolet spectra". Astronomy and Astrophysics. 404 (2): 689–700. Bibcode:2003A&A...404..689N. doi:10.1051/0004-6361:20030546.. "The fractional abundance relative to the Sun is given by:
10^−0.13 = 0.74, or 74%."

[SIMBAD-12] "LTT 8869 -- High proper-motion Star". SIMBAD (in Engels). Centre de Données astronomiques de Strasbourg. Geargiveer vanaf die oorspronklike op 16 Maart 2016. Besoek op 24 Desember 2011.

[Bowditch-13] Bowditch, LL.D., Nathaniel (2002) [1802]. "15: Navigational Astronomy" (PDF). The American Practical Navigator: An Epitome of Navigation. Bethesda, MD: National Imagery and Mapping Agency. p. 248. ISBN 978-0-939837-54-0. Geargiveer vanaf die oorspronklike (PDF) op 30 November 2016. Besoek op 20 September 2016.

[kunitzsch_smart2006-14] Kunitzsch, P.; Smart, T. (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd uitg.). Cambridge, Massachusetts: Sky Publishing. p. 39. ISBN 978-1-931559-44-7.

[WGSN-15] Verwysingfout: Invalid <ref> tag; no text was provided for refs named WGSN

[IAU-CSN-16] "IAU Catalog of Star Names" (in Engels). Geargiveer vanaf die oorspronklike op 20 April 2020. Besoek op 28 Julie 2016.

[allen1963-17] Allen, Richard H. (1963). Star Names: Their Lore and Meaning (herdruk uitg.). New York, NY: Dover Publications Inc. p. 237. ISBN 978-0-486-21079-7.

[mnras389_2_869-18] 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.

[lang2006-19] Lang, Kenneth R. (2006). Astrophysical formulae. Astronomy and astrophysics library. Vol. 1 (3rd uitg.). Birkhäuser. ISBN 978-3-540-29692-8.. "The radius (R_*) is given by:
${\begin{aligned}2\cdot R_{*}&={\frac {(10^{-3}\cdot 31\cdot 1.02)\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 6.8\cdot R_{\bigodot }\end{aligned}}$ "

[apj732_2_61-20] Zuckerman, B.; et al. (Mei 2011). "The Tucana/Horologium, Columba, AB Doradus, and Argus Associations: New Members and Dusty Debris Disks". The Astrophysical Journal. 732 (2): 61. arXiv:1104.0284. Bibcode:2011ApJ...732...61Z. doi:10.1088/0004-637X/732/2/61.

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