Nuclear burning rates and Population II stellar models |
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| Authors: | E Brocato V Castellani & F L Villante |
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| Institution: | Osservatorio Astronomico Collurania, I-64100 Teramo, Italy,;Istituto Nazionale Fisica Nucleare, LNGS, I-67100 Assergi, Italy,;Dipartimento di Fisica, Universitádegli studi di Pisa, I-56100 Pisa, Italy,;Dipartimento di Fisica, Universitádegli studi de L'Aquila, I-67100 L'Aquila, Italy |
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| Abstract: | We discuss theoretical predictions concerning the evolution of globular cluster Population II stars with respect to current estimates of standard errors in the determination of nuclear burning rates. Numerical evaluations are given for the dependence of the turn-off and horizontal branch luminosities on the rate of the relevant nuclear reactions. We conclude that evolutionary predictions appear rather solid in this respect, with a maximum 3 σ error of about 1 Gyr in the evaluation of cluster ages derived from the calibration of the difference in luminosity between the horizontal branch and the turn-off. However, current evaluation of the original He content, as given on the basis of the R -parameter, will need to wait for a much better determination of the 12C(α, γ)16O reaction before reaching a satisfactory accuracy. |
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| Keywords: | nuclear reactions nucleosynthesis abundances stars: evolution stars: Population II globular clusters: general |
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