Diffusion coefficients in the envelopes of white dwarfs

Understand

The diffusion of elements is a key process in understanding the unusual surface composition of white dwarfs stars and their spectral evolution.

• The diffusion coefficients of Paquette et al.
• (1986) have been widely used to model diffusion in white dwarfs.
• We perform new calculations of the coefficients of inter-diffusion and ionic thermal diffusion with 1) a more advanced model that uses a recent modification of the calculation of the collision integrals that is more suitable for the partially ionized, partially degenerate and moderately coupled plasma, and 2) classical molecular dynamics.