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 _ { ub } , is related to the initial binary separation , a , by a power law of the form \delta M _ { 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 } .