The mixing of internal gravity waves and lithium production in intermediate-mass AGB stars

Abstract

Context: Intermediate-mass asymptotic giant branch (AGB) stars influence Galactic lithium evolution by ejecting surface material (including Li) via stellar winds. Internal gravity waves (IGW), excited by convective motions, drive turbulent mixing in non-convective regions, altering stellar surface and wind chemistry. Aims: Investigate IGW-induced extra-mixing in the radiative zone between thermal pulses and convective envelopes of AGB stars and its impact on Li production. Derive the total Li contribution from intermediate-mass AGB stars using stellar models and initial mass functions. Methods: Construct stellar models (from zero-age main sequence to AGB end) with MESA, incorporating IGW-induced mixing and element diffusion. Calculate Li yields for stars of varying masses and metallicities using grids and population synthesis. Results: IGW triggers extra-mixing during He-shell flashes, transporting Be-7 from the radiative zone to the convective envelope, where it decays into Li-7. The positive effect of IGW on Li yield decreases with initial stellar mass but increases with metallicity. Most AGB stars (3.5-7.5 solar masses) produce positive Li yields. The total Li yield with IGW mixing (approximately 15 solar masses) is twice that without, contributing about 10 percent to Galactic Li. Conclusions: Through this extra-mixing mechanism induced by IGW, AGB stars can achieve a maximum A(Li) exceeding 5 and intermediate-mass AGB stars significantly contribute to Li in the Galactic ISM. These findings underscore the crucial role of IGW in stellar evolution, particularly in enhancing Li production.

arXiv commentAbstract edited (deletions & abbrev.) to meet char. limit. 11 pages, 9 figures, 2 tables. Accepted for publication in A&A

References in corpus (45)

• The chemical composition of the Sun
• On the variation of the Initial Mass Function
• Modules for Experiments in Stellar Astrophysics (MESA)
• Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars
• Modules for Experiments in Stellar Astrophysics (MESA): Binaries, Pulsations, and Explosions
• Modules for Experiments in Stellar Astrophysics (MESA): Convective Boundaries, Element Diffusion, and Massive Star Explosions
• Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
• On the volume of the set of mixed entangled states
• Low Temperature Opacities
• The Dawes Review 2: Nucleosynthesis and stellar yields of low and intermediate-mass single stars
• Element Diffusion in the Solar Interior
• Abundances and Kinematics of Field Halo and Disk Stars I: Observational Data and Abundance Analysis
• Influence of gravity waves on the internal rotation and Li abundance of solar-type stars
• Toward a Unification of Star Formation Rate Determinations in the Milky Way and Other Galaxies
• Stellar yields from metal-rich asymptotic giant branch models
• Stellar Turbulent Convection: A Selfconsistent Model
• Full computation of massive AGB evolution. I. The large impact of convection on nucleosynthesis
• Massive AGB models of low metallicity: the implications for the self-enrichment scenario in metal poor Globular Clusters
• Production and evolution of Li, Be and B isotopes in the Galaxy
• Standard big bang nucleosynthesis and primordial CNO Abundances after Planck
• Internal Gravity Wave Excitation by Turbulent Convection
• Lithium and zirconium abundances in massive Galactic O-rich AGB stars
• Galactic chemical evolution of Lithium: interplay between stellar sources"
• The stellar origin of 7Li - Do AGB stars contribute a substantial fraction of the local Galactic lithium abundance?
• Hot bottom burning and s-process nucleosynthesis in massive AGB stars at the beginning of the thermally-pulsing phase
• The nature of the Li enrichment in the most Li-rich giant star
• Highly Enriched 7Be in the ejecta of Nova Sagittarii 2015 No. 2 (V5668 Sgr) and the Galactic Lithium origin
• Survey of Li-rich giants among Kepler and LAMOST fields: Determination of Li-rich giants Evolutionary Phase
• A helium-flash-induced mixing event can explain the lithium abundances of red clump stars
• The role of lithium production in massive AGB and super--AGB stars for the understanding of multiple populations in Globular Clusters
• The evolutionary state of Miras with changing pulsation periods
• Theoretical Estimates of Stellar e-Captures. I. The half-life of 7Be in Evolved Stars
• Circumstellar effects on the Rb abundances in O-rich AGB stars
• 3D hydrodynamic simulations of massive main-sequence stars. I. Dynamics and mixing of convection and internal gravity waves
• Tracking the evolution of lithium in giants using asteroseismology: Super-Li-rich stars are almost exclusively young red-clump stars
• Turbulent transport in a strongly stratified forced shear layer with thermal diffusion
• Formation and Destiny of White Dwarf and Be Star Binaries
• Rubidium and zirconium abundances in massive Galactic asymptotic giant branch stars revisited
• The effects of a revised ${}^7$Be e${}^{-}$-capture rate on solar neutrino fluxes
• Possible Formation Scenarios of ZTF J153932.16+502738.8-A Gravitational Source Close to the Peak of LISA's Sensitivity
• Li-rich and super Li-rich giants produced by element diffusion
• The population synthesis of Wolf-Rayet stars involving binary merger channels
• Novae: An Important Source of Lithium in the Galaxy
• Exploring circumstellar effects on the lithium and calcium abundances in massive Galactic O-rich AGB stars
• The Impact of Neutrino Magnetic Moments on the Evolution of the Helium Flash and Lithium-Rich Red Clump Stars