  The impact of Type Ia supernova ejecta on a helium-star companion is
investigated via high-resolution, two-dimensional hydrodynamic simulations. For
a range of helium-star models and initial binary separations it is found that
the mass unbound in the interaction, $\delta M_{\rm ub}$, is related to the
initial binary separation, $a$, by a power law of the form $\delta M_{\rm ub}
\propto a^{m}$. This power-law index is found to vary from -3.1 to -4.0,
depending on the mass of the helium star. The small range of this index
brackets values found previously for hydrogen-rich companions, suggesting that
the dependence of the unbound mass on orbital separation is not strongly
sensitive to the nature of the binary companion. The kick velocity is also
related to the initial binary separation by a power law with an index in a
range from -2.7 to -3.3, but the power-law index differs from those found in
previous studies for hydrogen-rich companions. The space motion of the
companion after the supernova is dominated by its orbital velocity in the
pre-supernova binary system. The level of Ni/Fe contamination of the companion
resulting from the passage of the supernova ejecta is difficult to estimate,
but an upper limit on the mass of bound nickel is found to be $\sim 5\times
10^{-4}\ M_\odot$.
