s Process in low-mass Asymptotic Giant Branch Stars

Abstract

The main component of the s process is produced by low mass stars (between 1.5 and 3 Mo), when they climb for the second time the red giant branch and experience a series of He shell flashes called thermal pulses. During the relatively long period (10^5 yr) that elapses between two subsequent thermal pulses, a slow neutron flux is provided by the 13C(a,n)16O reaction taking place within a thin 13C pocket located in the He-rich and C-rich mantel of these stars. A second, marginal, neutron burst occurs during the thermal pulse and it is powered by the 22Ne(a,n)25Mg reaction. We review the present status of the nucleosynthesis models of low mass AGB stars. The advance in the knowledge of the complex coupling between convective mixing and nuclear process, which allows the surface enrichment of C and s-process elements, is presented, together with the hypotheses concerning the physical mechanism driving the formation of the 13C pocket. In order to illustrate the capabilities and the limits of the theory, an updated computation of a 2 Mo stellar structure with solar chemical composition is reported. This model has been obtained by including a full nuclear network (from H up to Bi, at the termination point of the s-process path) into the stellar evolution code. The predicted modification of the surface composition occurring during the AGB evolution is shown. The new challenge of AGB modeling, namely the study of C-rich and s-rich very metal-poor stars, is discussed.

arXiv commentpages 35

References in corpus (26)

• Neutron capture in low mass Asymptotic Giant Branch stars: cross sections and abundance signatures
• Astrophysical Reaction Rates From Statistical Model Calculations
• Line formation in solar granulation: IV. [O I], OI and OH lines and the photospheric O abundance
• Shell-model calculations of stellar weak interaction rates: II. Weak rates for nuclei in the mass range A=45-65 in supernovae environment
• Galactic Evolution of Sr, Y, Zr: A Multiplicity of Nucleosynthetic Processes
• A Reappraisal of the Solar Photospheric C/O Ratio
• Nucleosynthesis and mixing on the Asymptotic Giant Branch. III. Predicted and observed s-process abundances
• Cool bottom processes on the thermally-pulsing AGB and the isotopic composition of circumstellar dust grains
• Is HE0107-5240 A Primordial Star? -- The Characteristics of Extremely Metal-Poor Carbon-Rich Stars --
• Models of circumstellar molecular radio line emission: Mass loss rates for a sample of bright carbon stars
• s-Process Nucleosynthesis in Carbon Stars
• The Kr85 s-process Branching and the Mass of Carbon Stars
• Nucleosynthesis of light elements inside thermally pulsing AGB stars I: the case of intermediate-mass stars
• Obscured Asymptotic Giant Branch Variables in the Large Magellanic Cloud and the Period-Luminosity Relation
• Intermediate mass stars: updated models
• Evolution and Yields of Extremely Metal Poor Intermediate Mass Stars
• The s-Process in Rotating Asymptotic Giant Branch Stars
• Low mass AGB stellar models for 0.003 < Z < 0.02: basic formulae for nucleosynthesis calculations
• Evolution and Nucleosynthesis of Zero Metal Intermediate Mass Stars
• Abundance Analyses of Field RV Stars, V: DS Aquarii, UY Arae, TW Camelopardis, BT Librae, U Moncerotis, TT Ophiuchi, and RV Tauri
• A study of the s-process in the carbon-rich post-AGB stars IRAS06530-0213 and IRAS08143-4406 on the basis of VLT-UVES spectra
• Nucleosynthesis of s-elements in zero-metal AGB stars
• Constraints on the ${}^{22}Ne(\alpha ,n{)}^{25}$Mg s-process neutron source from analysis of ${}^{nat}Mg+n$ total and ${}^{25}Mg(n,\gamma )$ cross sections
• Lifetimes of 26Al and 34Cl in an astrophysical plasma
• First detection of a lithium rich carbon star in the Draco dwarf galaxy: evidence for a young stellar population
• Direct neutron capture cross sections of 62Ni in the s-process energy range

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