Stellar burning

Over the 13.7 billion years since the Big Bang, stars have burned nuclear fuel to maintain pressure support against gravitational contraction. In doing so, they have converted the hydrogen and helium left over from the Universe s earliest moments into the heavier elements that make nearly all of chemistry possible. This paper briefly reviews the evolution of stars, the mainline stages of stellar burning, and the side reactions that make Nature s heaviest elements. 

The Mainline Stages of Stellar Burning and Their Products... 

A rearrangement of lighter elements into elements heavier than iron or nickel leads to a decrease in nuclear binding energy per nucleon. This is the reason that iron and nickel are the end points of mainline stellar burning. Nevertheless, heavier elements can be made via side reactions to the mainline burning or in explosive burning when excess free nucleons allow capture beyond iron. 

The universal abundance of deuterium is the subject of ongoing investigation. All deuterium nuclei formed a few minutes after the big bang, providing the basis for the heavier elements. It is understood to be consumed solely by stellar burning—the nuclear fusion process in stars. New observational results, however, show that universal abundance is about 20 percent more than projected under this scenario. This offers spectroscopists and theorists new channels of exploration. 

As it has been seen in the preceding sections, stellar burning phases only lead to the production of nuclei up to Fe. A review by National Research CouncU of the National Academies identified 11 key questions to be addressed in science in the next decade (Turner et al. 2003). Ranked three on the list is How were the elements fi om Fe to U produced Although the ground to answer this question has been laid by Burbidge et al. (1957), Cameron (1957) and much progress has... 

Following their creation in the thermonuclear processes that might be termed stellar burning , the elements heavier than Li, principally carbon, nitrogen and oxygen, are dispersed into interstellar space by stellar winds or supemovae explosions that mark the death of certain stars. The abundances of the chemical elements have been estimated (with difficulty) by a number of authors. They do vary in different regions of the cosmos [3]. The abundances in the solar system are estimated from observations on the sun and on meteorites. Those given by Cameron [4] have been... 

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