Alnilam

	Alnilam
	Alnilam verlig NGC 1990 (foto deur Glen Youman).
Sterrebeeld	Jagter
Spektraaltipe	B0 Ia
Soort	Blouwit superreus
	Waarnemingsdata (Epog J2000)
Regte klimming	05h 36m 12.8s
Deklinasie	-01° 12′ 06.9″
Skynmagnitude (m)	1,69 (1,64-1,74)
Absolute magnitude (M)	-6,95
B-V-kleurindeks	-0,18
U-B-kleurindeks	-1,03
	Besonderhede
Massa (M☉)	30-64,5
Radius (R☉)	42
Ligsterkte (L☉)	832 000
Ouderdom (jaar)	5,7 miljoen
Temperatuur (K)	27 000
Rotasiespoed (km/s)	40-70
	Eienskappe
Veranderlikheid	α Cygni
	Ander name
	ε Ori, 46 Orionis, 112 G Orionis, HR 1903, BD -01°969, HD 37128, SAO 132346, FK5 210, HIP 26311, TD1 4963
Portaal	Sterrekunde

Alnilam, ook bekend as Epsilon Orionis en 46 Orionis, is ’n groot blou superreus sowat 2 000 ligjare van die Aarde af in die sterrebeeld Jagter. Dit is na raming 275 000 tot 537 000 keer so helder soos die Son, en sy massa is omtrent 34 keer dié van die Son.

Beskrywing

Alnilam is die 29ste helderste ster in die naglug en die 4de helderste in die Jagter; dit is ’n blouwit superreus. Saam met Mintaka en Alnitak vorm dit die Jagter se Belt, of Drie Konings. Alnilam is die middelste ster. Dit is effens veranderlik, van magnitude 1,64 tot 1,74. Sedert 1943 dien sy spektrum as een van die stabiele ankerpunte waarvolgens ander sterre geklassifiseer word.^[1] Dit is ook een van die 58 sterre wat snags vir navigasie gebruik word.

Binne die volgende miljoen jaar kan die ster ’n rooi superreus word en as ’n supernova ontplof. Dit word omring deur ’n molekulêre wolk, NGC 1990, wat deur Alnilam verlig word en dus ’n refleksienewel is. Die ster se winde bereik snelhede van tot 2 000 km/s, wat veroorsaak dat dit 20 miljoen keer vinniger as die Son massa verloor.^[8]

Naam

Die tradisionele naam Alnilam kom van die Arabiese naam النيلم (Al-nilam), wat verwant is aan die woord nilam "saffier". Ander spellings is Alnihan en Alnitam:^[9] Al drie spellings is blykbaar transliterasie- of kopieerfoute.^[10] In 2016 het die Internasionale Astronomiese Unie ’n werksessie gereël^[11] om stername te standaardiseer en katalogiseer. Daar is op die naam Alnilam vir dié ster besluit.^[12]

Verwysings

↑ ^1,0 ^1,1 Morgan, W. W.; Keenan, Philip C.; Kellman, Edith (1943). "An Atlas Of Stellar Spectra". Astrophysics Monographs.
↑ ^2,0 ^2,1 van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy & 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 Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
↑ ^4,0 ^4,1 Ruban, E. V.; Alekseeva, G. A.; Arkharov, A. A.; Hagen-Thorn, E. I.; Galkin, V. D.; Nikanorova, I. N.; Novikov, V. V.; Pakhomov, V. P.; Puzakova, T. Yu. (September 2006). "Spectrophotometric observations of variable stars". Astronomy Letters. 32 (9): 604–607. Bibcode:2006AstL...32..604R. doi:10.1134/S1063773706090052.
↑ Searle, S. C.; Prinja, R. K.; Massa, D.; Ryans, R. (2008). "Quantitative studies of the optical and UV spectra of Galactic early B supergiants. I. Fundamental parameters". Astronomy and Astrophysics. 481 (3): 777–97. arXiv:0801.4289. Bibcode:2008A&A...481..777S. doi:10.1051/0004-6361:20077125.
↑ ^6,0 ^6,1 ^6,2 ^6,3 ^6,4 Raul E. Puebla; D. John Hillier; Janos Zsargó; David H. Cohen; Maurice A. Leutenegger (2015). "X-ray, UV and optical analysis of supergiants: ε Ori". Monthly Notices of the Royal Astronomical Society. 456 (3): 2907. arXiv:1511.09365. Bibcode:2016MNRAS.456.2907P. doi:10.1093/mnras/stv2783.
↑ Voss, R.; Diehl, R.; Vink, J. S.; Hartmann, D. H. (2010). "Probing the evolving massive star population in Orion with kinematic and radioactive tracers". Astronomy and Astrophysics. 520: 10. arXiv:1005.3827. Bibcode:2010A&A...520A..51V. doi:10.1051/0004-6361/201014408. A51.
↑ ^8,0 ^8,1 Crowther, P. A.; Lennon, D. J.; Walborn, N. R. (Januarie 2006). "Physical parameters and wind properties of galactic early B supergiants". Astronomy & Astrophysics. 446 (1): 279–293. arXiv:astro-ph/0509436. Bibcode:2006A&A...446..279C. doi:10.1051/0004-6361:20053685.
↑ Allen, Richard Hinckley (1936). Star-names and their meanings. pp. 314–315.
↑ Knobel, E. B. (September 1909). "The name of epsilon Orionis". The Observatory. 32: 357. Bibcode:1909Obs....32..357K.
↑ "IAU Working Group on Star Names (WGSN)" (in Engels). Geargiveer vanaf die oorspronklike op 23 April 2020. Besoek op 22 Mei 2016.
↑ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Besoek op 28 Julie 2016.

Eksterne skakels

Alnilam 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

[mkk-1] 1,0 ^1,1 Morgan, W. W.; Keenan, Philip C.; Kellman, Edith (1943). "An Atlas Of Stellar Spectra". Astrophysics Monographs.

[hipparcos-2] 2,0 ^2,1 van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy & Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.

[ducati-3] 3,0 ^3,1 ^3,2 Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.

[ruban-4] 4,0 ^4,1 Ruban, E. V.; Alekseeva, G. A.; Arkharov, A. A.; Hagen-Thorn, E. I.; Galkin, V. D.; Nikanorova, I. N.; Novikov, V. V.; Pakhomov, V. P.; Puzakova, T. Yu. (September 2006). "Spectrophotometric observations of variable stars". Astronomy Letters. 32 (9): 604–607. Bibcode:2006AstL...32..604R. doi:10.1134/S1063773706090052.

[Searle_2008-5] Searle, S. C.; Prinja, R. K.; Massa, D.; Ryans, R. (2008). "Quantitative studies of the optical and UV spectra of Galactic early B supergiants. I. Fundamental parameters". Astronomy and Astrophysics. 481 (3): 777–97. arXiv:0801.4289. Bibcode:2008A&A...481..777S. doi:10.1051/0004-6361:20077125.

[puebla-6] 6,0 ^6,1 ^6,2 ^6,3 ^6,4 Raul E. Puebla; D. John Hillier; Janos Zsargó; David H. Cohen; Maurice A. Leutenegger (2015). "X-ray, UV and optical analysis of supergiants: ε Ori". Monthly Notices of the Royal Astronomical Society. 456 (3): 2907. arXiv:1511.09365. Bibcode:2016MNRAS.456.2907P. doi:10.1093/mnras/stv2783.

[Voss_2010-7] Voss, R.; Diehl, R.; Vink, J. S.; Hartmann, D. H. (2010). "Probing the evolving massive star population in Orion with kinematic and radioactive tracers". Astronomy and Astrophysics. 520: 10. arXiv:1005.3827. Bibcode:2010A&A...520A..51V. doi:10.1051/0004-6361/201014408. A51.

[crowther-8] 8,0 ^8,1 Crowther, P. A.; Lennon, D. J.; Walborn, N. R. (Januarie 2006). "Physical parameters and wind properties of galactic early B supergiants". Astronomy & Astrophysics. 446 (1): 279–293. arXiv:astro-ph/0509436. Bibcode:2006A&A...446..279C. doi:10.1051/0004-6361:20053685.

[allen-9] Allen, Richard Hinckley (1936). Star-names and their meanings. pp. 314–315.

[10] Knobel, E. B. (September 1909). "The name of epsilon Orionis". The Observatory. 32: 357. Bibcode:1909Obs....32..357K.

[WGSN-11] "IAU Working Group on Star Names (WGSN)" (in Engels). Geargiveer vanaf die oorspronklike op 23 April 2020. Besoek op 22 Mei 2016.

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

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