1993/04/06 by Anne A. Thoul, John N. Bahcall, Abraham Loeb · 1 citation
Physics and Astronomy · #astro-ph
paper · pdf · doi:10.1086/173695
published as Astrophys.J. 421 (1994) 828-842 · TeX document, 25 pages, for hardcopy with figures contact [email protected]. Institute for Advanced Study number AST 93/17
arxiv created 1993/04/06 · arxiv updated 2009/12/01
We study the diffusion of helium and other heavy elements in the solar interior by solving exactly the set of flow equations developed by Burgers for a multi-component fluid, including the residual heat-flow terms. No approximation is made concerning the relative concentrations and no restriction is placed on the number of elements considered. We give improved diffusion velocities for hydrogen, helium, oxygen and iron, in the analytic form derived previously by Bahcall and Loeb. These expressions for the diffusion velocities are simple to program in stellar evolution codes and are expected to be accurate to ∼ 15%. Our complete treatment of element diffusion can be directly incorporated in a standard stellar evolution code by means of an exportable subroutine, but, for convenience, we also give simple analytical fits to our numerical results.