The surface carbon and nitrogen abundances in models of ultra metal-poor stars

Abstract

We investigate whether the observed high number of carbon- and nitrogen-enhanced extremely metal-poor stars could be explained by peculiar evolutionary properties during the core He flash at the tip of the red giant branch. For this purpose we compute a series of detailed stellar models expanding upon our previous work; in particular, we investigate if during the major He flash the penetration of the helium convective zone into the overlying hydrogen-rich layers can produce carbon- and nitrogen-rich abundances in agreement with current spectroscopic observations. The dependence of this phenomenon on selected model input parameters, such as initial metallicity and treatment of convection is examined in detail.

arXiv comment8 pages, 4 figures, submitted to A&A

References in corpus (17)

• The Nucleosynthetic Signature of Population III
• The Formation of the First Star in the Universe
• The Formation of the First Stars. I. The Primordial Star Forming Cloud
• Solar Fusion Cross Sections
• Element Diffusion in the Solar Interior
• Extremely Metal-Poor Stars. VIII. High-Resolution, High-Signal-To-Noise Analysis of Five Stars with [Fe/H] < -3.5
• R-Process Abundances and Chronometers in Metal-Poor Stars
• Standard and Non-Standard Plasma Neutrino Emission Revisited
• Fossil Imprints of the First Generation Supernova Ejecta in Extremely Metal-Deficient Stars
• The Chemical Composition of Carbon-Rich, Very Metal-Poor Stars: A New Class of Mildly Carbon-Rich Objects Without Excess of Neutron-Capture Elements
• Structure, Evolution and Nucleosynthesis of Primordial Stars
• Evolution and Nucleosynthesis of Zero Metal Intermediate Mass Stars
• On the helium flash in low-mass Population III Red Giant stars
• Evolution of low-mass metal-free stars including effects of diffusion and external pollution
• Age-luminosity relations for low-mass metal-poor stars
• Microscopic diffusion of partly ionized metals in the Sun and metal-poor stars
• Lithium depletion in the sun: a study of mixing based on hydrodynamical simulations

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• The Origin of Carbon-Enhancement and Initial Mass Function of Extremely Metal-Poor Stars in the Galactic Halo
• CS 30322-023: an ultra metal-poor TP-AGB star?
• First full evolutionary computation of the He-flash induced mixing in Population II stars
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• Induced Formation of Primordial Low-Mass Stars
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