The evolutionary behaviour of population III intermediate mass stars |
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| Authors: | D Eryurt-Ezer N Kizilo?lu |
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| Institution: | (1) Physics Dept, Middle East Technical University, Ankara, Turkey |
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| Abstract: | Assuming the Big-Bang nucleosynthesis was responsible for the formation of helium, the evolution of first-generation intermediate-mass stars of 5, 7, and 9M
 with no metals have been studied from the threshold of stability through the stage of helium exhaustion in the cores of the stars. Hydrogen Main-Sequence positions are marked at effective temperatures higher than those of normal stars. The evolutionary tracks during the hydrogen burning phase start to be similar to those of normal stars when the CN-cycle reactions, which are controlled by the triple-alpha reactions, become operative for hydrogen depletion. Helium Main Sequence of Population III stars of intermediate mass occurs at the high effective temperature region of the H-R diagram and stars stay as blue stars until the end of the core helium exhaustion phase. The total time elapsed is in the range of 3×107 and 108yr. The stars with the initial masses of 5, 7, and 9M
developed a moderately electron degenerate complete hydrogen-exhausted region with masses of 0.77, 1.06, and 1.42M
, respectively, in which the most abundant element is carbon. |
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