Evolution of low-mass metal-free stars including effects of diffusion and external pollution

Abstract

We investigate the evolution of low-mass metal-free Population III stars. Emphasis is laid upon the question of internal and external sources for CNO-elements, which - if present in sufficient amounts in the hydrogen-burning regions - lead to a strong modification of the stars' evolutionary behavior. For the production of carbon due to nuclear processes inside the stars, we use an extended nuclear network, demonstrating that hot pp-chains do not suffice to produce enough carbon or are less effective than the triple3-alpha-process. As an external source of CNO-elements we test the efficiency of pollution by a nearby massive star combined with particle diffusion. For all cases investigated, the additional metals fail to reach nuclear burning regions before deep convection on the Red Giant Branch obliterates the previous evolution. The surface abundance history of the polluted Pop III stars is presented. The possibilities to discriminate between a Pop II and a polluted Pop III field star are also discussed.

arXiv commentAccepted for publication in ApJ

References in corpus (6)

• Element Diffusion in the Solar Interior
• A consistent explanation for ${}^{12}$C/${}^{13}$C, ${}^7$Li, and ${}^3$He anomalies in red giant stars
• A critical investigation on the discrepancy between the observational and theoretical Red Giant luminosity function "Bump"
• Fossil Imprints of the First Generation Supernova Ejecta in Extremely Metal-Deficient Stars
• A new analysis of the Red Giant Branch "Tip" distance scale and the value of the Hubble constant
• Primordial Nucleosynthesis and the Abundances of Beryllium and Boron

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