  We carried out 3D smoothed particle hydrodynamics simulations of the common
envelope binary interaction using the approximation of Bowen to calculate the
dust opacity in order to investigate the resulting dust-driven accelerations.
We have simulated two types of binary star: a 1.7 and a 3.7 $M_{\odot}$
thermally-pulsating, asymptotic giant branch stars with a 0.6 $M_{\odot}$
companion. We carried out simulations using both an ideal gas and a tabulated
equations of state, with the latter considering the recombination energy of the
envelope. We found that the dust-driven wind leads to a relatively small
increase in the unbound gas, with the effect being smaller for the tabulated
equation of state simulations and for the more massive primary. Dust
acceleration does contribute to envelope expansion with only a slightly
elongated morphology, if we believe the results from the tabulated equation of
state as more reliable. The Bowen opacities in the outer envelopes of the two
models, at late times, are large enough that the photosphere of the
post-inspiral object is about ten times larger compared to the same without
accounting for the dust opacities. As such, the prediction of the appearance of
the transient would change substantially if dust is included.
