  Recent gravitational wave observations include possible detections of black
hole - neutron star binary mergers. As with binary black hole mergers,
numerical simulations help characterize the sources. For binary systems with
neutron star components, the simulations help to predict the imprint of tidal
deformations and disruptions on the gravitational wave signals. In a previous
study, we investigated how the mass of the black hole has an impact on the
disruption of the neutron star and, as a consequence, on the shape of the
gravitational waves emitted. We extend these results to study the effects of
varying the compactness of the neutron star. We consider neutron star
compactness in the 0.123 to 0.2 range for binaries with mass ratios of 3 and 5.
As the compactness and the mass ratio increase, the binary system behaves
during the late inspiral and merger more like a black hole binary. For the case
with the highest mass ratio and most compact neutron star, the gravitational
waves emitted, in terms of mismatches, are almost indistinguishable from those
by a binary black hole. The disruption of the star significantly suppresses the
kicks on the final black hole. The disruption also affects, although not
dramatically, the spin of the final black hole. Lastly, for neutron stars with
low compactness, the quasi-normal ringing of the black hole after the merger
does not show a clean quasi-normal ringing because of the late accretion of
debris from the neutron star.
