  The excitation of neutron stars is expected to be an important source of
gravitational radiation. Of fundamental importance is then to investigate
mechanisms that trigger oscillations in neutron stars in order to characterize
the emitted radiation. We present results from a numerical study of the
even-parity gravitational radiation generated from a particle orbiting a
neutron star. We focus our investigation on those conditions on the orbital
parameters that favor the excitation of $w$-modes. We find that, for
astrophysically realistic conditions, there is practically no $w$-mode
contribution to the emitted radiation. Only for particles with
ultra-relativistic orbital speeds $\ge 0.9c$, the $w$-mode does significantly
contribute to the total emitted gravitational energy. We also stress the
importance of setting consistent initial configurations.
