  The neutron rich isotope 22Ne may be a significant impurity in carbon and
oxygen white dwarfs and could impact how the stars freeze. We perform molecular
dynamics simulations to determine the influence of 22Ne in carbon-oxygen-neon
systems on liquid-solid phase equilibria. Both liquid and solid phases are
present simultaneously in our simulation volumes. We identify liquid, solid,
and interface regions in our simulations using a bond angle metric. In general
we find good agreement for the composition of liquid and solid phases between
our MD simulations and the semi analytic model of Medin and Cumming. The trace
presence of a third component, neon, does not appear to strongly impact the
chemical separation found previously for two component carbon and oxygen
systems. This suggests that small amounts of 22Ne may not qualitatively change
how the material in white dwarf stars freezes. However, we do find
systematically lower melting temperatures (higher Gamma) in our MD simulations
compared to the semi analytic model. This difference seems to grow with
impurity parameter Q_imp and suggests a problem with simple corrections to the
linear mixing rule for the free energy of multicomponent solid mixtures that is
used in the semi analytic model.
