Magelanski oblaci
Magelanski oblaci (ili Nubeculae Magellani[2]) dve su nepravilne patuljaste galaksije vidljive na Južnoj nebeskoj hemisferi. One su članovi Lokalne grupe i orbitiraju galaksiju Mlečni put. Pošto obe pokazuju znakove spiralne strukture, često su klasifikovane kao Magelanske spiralne galaksije. Dve galaksije su:
- Veliki Magelanov oblak (LMC), udaljen oko 163.000 svetlosnih godina[3][4]
- Mali Magelanov oblak (SMC), udaljen oko 206.000 svetlosnih godina[5][6]
Istorija
[уреди | уреди извор]Magelanski oblaci su bili poznati još od starih vremena domorodačkim narodima Južne Amerike i Afrike, a od prvog milenijuma u Zapadnoj Aziji. Veruje se da je prvo sačuvano pominjanje velikih Magelanskih oblaka u petroglifima i stenskim crtežima pronađenim u Čileu. Pretpostavlja se da su oni objetki koje pominje polihistor Ibn Kutajba (umro 889. godine pne) u svojoj knjizi Al-Anva (posmatranje Meseca u preislamskoj arapskoj kulturi):
- „وأسفل من سهيل قدما سهيل . وفى مجرى قدمى سهيل، من خلفهما كواكب زهر كبار، لا ترى بالعراق، يسميها أهل تهامة الأعبار
- I ispod Kanopusa, stoje stopala Kanopusa, a na njihovom produžetku, iza njih su sjajne velike zvezde, koja se ne vidi u Iraku, a narod Tihame ih naziva al-a‘bār.”[7]
Kasnije je Al Sufi, profesionalni astronom,[8] 964. godine u svojoj Knjizi fiksnih zvezda, pomenuo isti navod, ali sa različitim spelovanjem. Pod Argo Navisom, on je naveo da su „neimenovani drugi tvrdili da ispod Kanopusa postoje dve zvezde poznate kao 'noge Kanopusa', i da se ispod njih nalaze sjajne bele zvezde koje nisu viđene u Iraku, niti Nadždu, i da su ih stanovnici Tihame nazivali ih al-Bakar [krave], dok Ptolemej nije spomenuo ništa o tome, tako da mi [Al-Sufi] ne znamo da li je to istina ili neistina.”[9] Ibn Kutajba i Al-Sufi su verovatno citirali iz rada o Anvi poznatog naučnika Abu Hanifa Dinavarija, koje uglavnom nije sačuvano do današnjeg vremena. Abu Hanifa je verovatno citirao ranije izvore, koje su možda samo priče putnika, te otuda i Al Sufijevi komentari o njihovoj verodostojnosti.
Na Šri Lanci su se od davnina ovi oblaci nazivali Maha Mera Paruvataja, što znači „velika planina”, jer izgledaju kao vrhovi dalekog planinskog lanca.
U Evropi, o Oblacima su prvi izveštavali italijanski autori iz 16. veka Peter Martir d'Anghiera i Andrea Korsali, pri čemu su oba dela zasnovana na portugalskim putovanjima.[10][11] Potom je o Oblacima izvestio Antonio Pigafeta, koji je pratio ekspediciju Ferdinanda Magelana na njegovom obilaženju sveta 1519–1522.[12][2] Međutim, imenovanje oblaka po Magelanu nije postalo široko zastupljeno do znatno kasnijeg perioda. U Bajerovoj Uranometriji oni su označeni kao nubecula major i nubecula minor.[13] Na zvezdarskoj mapi iz 1756. godine francuskog astronoma Lakaja oni su označeni kao le Grand Nuage i le Petit Nuage („Veliki oblak” i „Mali oblak”).[14] Heršel iz Kejp opservatorije u Južnoj Africi je proveo 4 godine pišući izveštaj na 400 stranica koji je objavljen 1847. godine. U tom izveštaju je detaljno opisano preko hiljadu od mnogobrojnih zvezda, maglina i klastera koji sačinjavaju oblak koji je, čini se, bio zasebna udaljenija grupa od uobičajenih zvezda u Mlečnom putu, što je rani pokazatelj zasebne galaksije.
Reference
[уреди | уреди извор]- ^ „Media Advisory: Virtual Press Conference to Mark ALMA Inauguration”. ESO. Приступљено 3. 4. 2013.
- ^ а б Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint изд.). New York, NY: Dover Publications Inc. стр. 294–295.
- ^ Pietrzyński, G; D. Graczyk; W. Gieren; I. B. Thompson; B. Pilecki; A. Udalski; I. Soszyński; et al. (7. 3. 2013). „An eclipsing-binary distance to the Large Magellanic Cloud accurate to two per cent”. Nature. 495 (7439): 76—79. Bibcode:2013Natur.495...76P. PMID 23467166. arXiv:1303.2063
. doi:10.1038/nature11878.
- ^ Buscombe, William (1954). „Astronomical Society of the Pacific Leaflets, The Magellanic Clouds”. Astronomical Society of the Pacific Leaflets. 7 (302): 9. Bibcode:1954ASPL....7....9B.
- ^ „NASA/IPAC Extragalactic Database”. Results for Small Magellanic Cloud. Приступљено 1. 12. 2006.
- ^ Graczyk, Darius; Pietrzyński, Grzegorz; Thompson, Ian B.; Gieren, Wolfgang; Pilecki, Bogumił; et al. (2014). „The Araucaria Project. The Distance to the Small Magellanic Cloud from Late-type Eclipsing Binaries”. The Astrophysical Journal. 780 (1): 59. Bibcode:2014ApJ...780...59G. arXiv:1311.2340
- ^ „Al-Anwaa, Ibn Qutaybah”. Архивирано из оригинала 24. 07. 2017. г. Приступљено 4. 9. 2017.
- ^ „Observatoire de Paris (Abd-al-Rahman Al Sufi)”. Приступљено 22. 7. 2011.
- ^ „Book of Fixed Stars, Al-Sufi (manuscript written and illustrated by his son)”. Приступљено 22. 2. 2017.
- ^ For Peter Martyr d'Anghiera's mention of the Magellanic clouds, see:
- Petrus Martyr de Anghiera (1574) De rebus Oceanicis et Orbe Novo [Concerning the ocean and the new world] (Cologne, (Germany): Geruinum Calenium (Gerwin Calenius), 1574), decade 3, book 1, p. 217. (in Latin) From p. 217: "Assecuti sunt Portugallenses alterius poli gradum quintum & quinquagesimum amplius, ubi punctum, circumeuntes quasdam nubeculas licet intueri, veluti in lactea via sparsos fulgores per universum coeli globum intra eius spatii latitudinem." (The Portuguese reached beyond the 55th degree of the other pole, where one may observe certain nebulae revolving around the point [i.e., the southern celestial pole], scattered in the Milky Way like luminous patches throughout the whole sphere of the sky, within the breadth of its extent. [That is, nebulae appear in or beside the Milky Way throughout its entire length in the southern sky.])
- Humboldt, Alexander von, with E.C. Otte and B.H. Paul, trans., Cosmos: A Sketch of a Physical Description of the Universe (London, England: Henry G. Bohn, 1852), vol. 4, pp. 340–341.
- For further details of – and other editions of – Peter Martyr d'Anghiera's book De Orbe Novo, see Wikipedia's article: Decades of the New World
- ^ From 1515 to 1517, Andrea Corsali sailed to the East Indies and China in a Portuguese ship. In 1516, Andrea Corsali sent a letter to Giuliano de' Medici, Duke of Nemours, mentioning the Magellanic clouds. This letter was translated into English by Richard Eden (c.1520–1576) and published in 1555. The relevant part of Corsali's letter (translated by Eden) appears in:
- Richard Eden, with Edward Arber, ed., The First Three English Books on America … (Birmingham, England: 1885), "Of the pole antarike and the starres abowt the same … ", p. 279. Corsali said that his ship had passed the Cape of Good Hope ("the cape of Bona Speranza") and was at 37 degrees south latitude when he observed the Magellanic clouds: "Here we sawe a marueylous order of starres, so that in the parte of heauen contrary to owre northe pole, to know in what place and degree the south pole was, we tooke the day with the soonne, and obserued the nyght with the Astrolabie, and sawe manifestly twoo clowdes of reasonable bygnesse mouynge abowt the place of the pole continually now rysynge and nowe faulynge, so keepynge theyr continuall course in circular mouying, with a starre euer in the myddest which is turned abowt with them abowte xi degrees from the pole." ("Here we saw a marvelous arrangement of stars, so that in the part of heaven [that is] opposite our north [celestial] pole, in order to know in what place and degree [of latitude] the south [celestial] pole was, we [measured our position during] the day using the sun, and observed [our position during] the night using an astrolabe, and saw clearly two clouds of reasonable bigness revolving around the location of the [southern celestial] pole, continually now rising and now falling, thus maintaining their continual course of circular motion, with a star always in the middle [between them], which revolves with them about 11 degrees from the [south celestial] pole.")
- See also: Kanas, Nick, Star Maps: History, Artistry, and Cartography, 2nd ed. (New York, New York: Springer Science + Business Media, 2012), § 4.3.2.2 Andreas Corsali, p. 118.
- ^ Pigafetta et al., with Lord Stanley of Alderley, trans., The First Voyage Round the World, by Magellan (London, England: Hakluyt Society, 1874), p. 66. From p. 66: "The antarctic pole is not so covered with stars as the arctic, for there are to be seen there many small stars congregated together, which are like to two clouds a little separated from one another, and a little dimmed, ..."
- ^ Bayer, J., (1661) Uranometria, pl. Aaa (49) Архивирано на сајту Wayback Machine (22. јул 2011) U.S. Naval Observatory; retrieved on 2009-09-05
- ^ de Lacaille, N. L., (1756) Planisphere contenant les Constellations Celestes, Memoires Academie Royale des Sciences pour 1752. Архивирано 2009-05-09 на сајту Wayback Machine Linda Hall Library; retrieved on 2009-09-05
Literatura
[уреди | уреди извор]- Eric Chaisson and Steve McMillan, Astronomy Today (Englewood Cliffs: Prentice-Hall, Inc., 1993), p. 550.
- Michael Zeilik, Conceptual Astronomy (New York: John Wiley & Sons, Inc., 1993), pp. 357–8.
- „NAME Magellanic Stream”. SIMBAD. Centre de données astronomiques de Strasbourg.
- Discovery: Wannier, P.; Wrixon, G. T. (1972). „An Unusual High-Velocity Hydrogen Feature”. Astrophysical Journal. 173: L119 – L123. Bibcode:1972ApJ...173L.119W. doi:10.1086/180930.
- MC connection made: Mathewson, D. S.; Cleary, M. N.; Murray, J. D. (1974). „The Magellanic stream”. Astrophysical Journal. 190: 291–296. Bibcode:1974ApJ...190..291M. doi:10.1086/152875.
- Initial modelling: Murai, T.; Fujimoto, M. (1980). „The Magellanic Stream and the Galaxy with a Massive Halo”. Publications of the Astronomical Society of Japan. 32: 581–604. Bibcode:1980PASJ...32..581M.
- LAF discovery: Putman, M. E.; et al. (1998). „Tidal disruption of the Magellanic Clouds by the Milky Way”. Nature. 394 (6695): 752—754. Bibcode:1998Natur.394..752P. arXiv:astro-ph/9808023
- Yoshizawa, Akira M.; Noguchi, Masafumi (2003). „The dynamical evolution and star formation history of the Small Magellanic Cloud: effects of interactions with the Galaxy and the Large Magellanic Cloud”. MNRAS. 339 (4): 1135–1154. Bibcode:2003MNRAS.339.1135Y. doi:10.1046/j.1365-8711.2003.06263.x
- Mastropietro, C.; Moore, B.; Mayer, L.; Wadsley, J.; Stadel, J. (2005). „The gravitational and hydrodynamical interaction between the Large Magellanic Cloud and the Galaxy”. MNRAS. 363 (2): 509–520. Bibcode:2005MNRAS.363..509M. arXiv:astro-ph/0412312
- Connors, Tim W.; Kawata, Daisuke; Gibson, Brad K. (2005). „N-body simulations of the Magellanic Stream”. Monthly Notices of the Royal Astronomical Society. 371: 108—120. Bibcode:2006MNRAS.371..108C. arXiv:astro-ph/0508390
- Shattow, Genevieve; Loeb, Abraham (2009). „Implications of recent measurements of the Milky Way rotation for the orbit of the Large Magellanic Cloud”. Monthly Notices of the Royal Astronomical Society: Letters. 392 (1): L21—L25. Bibcode:2009MNRAS.392L..21S. arXiv:0808.0104
- Freedman, Wendy L.; Madore, Barry F. (2010). „The Hubble Constant”. Annual Review of Astronomy and Astrophysics. 48: 673—710. Bibcode:2010ARA&A..48..673F. arXiv:1004.1856
- Majaess, Daniel J.; Turner, David G.; Lane, David J.; Henden, Arne; Krajci, Tom (2010). „Anchoring the Universal Distance Scale via a Wesenheit Template”. Journal of the American Association of Variable Star Observers. 39 (1): 122. Bibcode:2011JAVSO..39..122M. arXiv:1007.2300
Spoljašnje veze
[уреди | уреди извор]
- Magellanic Clouds Working Group
- ESO: VISTA Peeks Through the Small Magellanic Cloud’s Dusty Veil incl. Fotos & Anomations
