exceto por um processo endotermico e, portanto, energia adicional so pode ser produzida pelo colapso gravitacional. [137]O exemplo abaixo mostra o tempo requerido para uma estrela de 20 massas solares consumir todo o seu combustivel nuclear. Como uma estrela da sequencia principal da classe O, ela teria 8 vezes o raio solar e 62.000 vezes a luminosidade do Sol. [139]MaterialcombustivelTemperatura(milhoes de kelvins)Densidade(kg/cm3)Duracao da queima( em anos)H370,00458,1 milhoesHe1880,971,2 milhoesC870170976Ne1.5703.1000,6O1.9805.5501,25S/Si3.34033.4000,0315[140]Referencias a b Bahcall, John N. (2000-06-29). How the Sun Shines. Nobel Foundation. Pagina visitada em 2006-08-30. a b c d Richmond, Michael. Late stages of evolution for low-mass stars. Rochester Institute of Technology. Pagina visitada em 2006-08-04. Stellar Evolution & Death. NASA Observatorium. Pagina visitada em 2006-06-08. a b Iben, Icko, Jr. (1991). "Single and binary star evolution". Astrophysical Journal Supplement Series 76: 55114. DOI:10.1086/191565. Bibcode: 1991ApJS...76...55I. a b Forbes, George. History of Astronomy. London: Watts & Co., 1909. Hevelius, Johannis. Firmamentum Sobiescianum, sive Uranographia. Gdansk: [s.n.], 1690. Tndering, Claus. Other ancient calendars. WebExhibits. Pagina visitada em 2006-12-10. von Spaeth, Ove (2000). "Dating the Oldest Egyptian Star Map". Centaurus International Magazine of the History of Mathematics, Science and Technology 42 (3): 159179. North, John. The Norton History of Astronomy and Cosmology. New York and London: W.W. Norton & Company, 1995. 3031 p. Murdin, P.. Encyclopedia of Astronomy and Astrophysics. [S.l.: s.n.], 2000November. Grasshoff, Gerd. The history of Ptolemy's star catalogue. [S.l.]: Springer, 1990. 15 p. Pinotsis, Antonios D.. Astronomy in Ancient Rhodes. Section of Astrophysics, Astronomy and Mechanics, Department of Physics, University of Athens. Pagina visitada em 2009-06-02. Clark, D. H.; Stephenson, F. R. (June 29, 1981). "The Historical Supernovae". Supernovae: A survey of current research; Proceedings of the Advanced Study Institute: 355370, Cambridge, England: Dordrecht, D. Reidel Publishing Co. Zhao, Fu-Yuan; Strom, R. G.; Jiang, Shi-Yang (2006). "The Guest Star of AD185 Must Have Been a Supernova". Chinese Journal of Astronomy and Astrophysics 6 (5): 635640. DOI:10.1088/1009-9271/6/5/17. Astronomers Peg Brightness of Historys Brightest Star. NAOA News (March 5, 2003). Pagina visitada em 2006-06-08. Frommert, Hartmut; Kronberg, Christine (August 30, 2006). Supernova 1054 - Creation of the Crab Nebula. SEDS. University of Arizona. Duyvendak, J. J. L. (April 1942). "Further Data Bearing on the Identification of the Crab Nebula with the Supernova of 1054 A.D. Part I. The Ancient Oriental Chronicles". Publications of the Astronomical Society of the Pacific 54 (318): 9194. DOI:10.1086/125409. Bibcode: 1942PASP...54...91D.Mayall, N. U. (April 1942). "Further Data Bearing on the Identification of the Crab Nebula with the Supernova of 1054 A.D. Part II. The Astronomical Aspects". Publications of the Astronomical Society of the Pacific 54 (318): 95104. DOI:10.1086/125410. Bibcode: 1942PASP...54...95M. Brecher, K.; et al. (1983). "Ancient records and the Crab Nebula supernova". The Observatory 103: 106113. Bibcode: 1983Obs...103..106B. Kennedy, Edward S. (1962). "Review: The Observatory in Islam and Its Place in the General History of the Observatory by Aydin Sayili". Isis 53 (2): 237239. DOI:10.1086/349558. Jones, Kenneth Glyn. Messier's nebulae and star clusters. [S.l.]: