Abundance anomalies in main-sequence stars - Competition between diffusion processes and turbulent motions

Abstract

view Abstract Citations (111) References (24) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Abundance anomalies in main-sequence stars: competition between diffusion processes and turbulent motions. Vauclair, G. ; Vauclair, S. ; Michaud, G. Abstract A 'turbulent diffusion coefficient' is introduced into the diffusion velocity for the purpose of studying the competition between diffusion processes, which force the elements toward radial inhomogeneous equilibrium distributions, and turbulence, which restores homogeneous chemical composition. Numerical simulations of abundance evolution in envelopes of main-sequence stars are presented for a few elements, and turbulence constraints which are compatible with an efficient diffusion method are established. A method for obtaining the equilibrium concentration distribution in the presence of turbulence is developed and applied to cool Am stars. It is shown that the underabundant elements impose stringent constraints on the strength of the turbulence present below the convection zone. Publication: The Astrophysical Journal Pub Date: August 1978 DOI: 10.1086/156324 Bibcode: 1978ApJ...223..920V Keywords: Main Sequence Stars; Metallic Stars; Particle Diffusion; Stellar Motions; Turbulence Effects; Abundance; Approximation; Atmospheric Turbulence; Chemical Composition; Convection; Diffusion Coefficient; Helium; Mercury (Metal); Scandium; Shear Flow; Stellar Envelopes; Strontium; Turbulent Boundary Layer; Turbulent Diffusion; Astrophysics; Atmospheres:Peculiar A Stars; Element Abundances:Main-Sequence Stars; Stellar Atmospheres:Turbulence full text sources ADS |