Turbulent diffusion in stars and the (12C/13C) abundance ratio.
Abstract
Very mild turbulence drives slow transport of chemical elements by turbulent diffusion within stars. Due to the strong gradient of C-13 generated by thermo-nuclear reactions, a flow of C-13 penetrates the outer part of a star during its life on the main sequence. The average C-13 concentration produced leads, at the time of appearance of the deep surface convective zone during the giant phase, to surface (C-12/C-13) abundance ratios close to the observed ratios. For a turbulent diffusion coefficient D = 200 nu, where nu is the microscopic viscosity, one obtains the following values of the mass (in solar units) and the surface abundance ratio: (1, 8.9); (1.6, 18.2); (2, 24.5). The value of Di is in agreement with that obtained previously by Schatzman (1977).
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- October 1979
- Bibcode:
- 1979A&A....78..323G
- Keywords:
-
- Abundance;
- Carbon Isotopes;
- Giant Stars;
- Stellar Atmospheres;
- Stellar Models;
- Turbulent Diffusion;
- Carbon 12;
- Carbon 13;
- Mass Ratios;
- Thermonuclear Reactions;
- Astrophysics;
- Carbon:Giants;
- Stellar Evolution:Turbulence