Excitation of neutron star oscillations by an orbiting particle - art. no.064019

The excitation of neutron stars is expected to be an important source of gr avitational radiation. Therefore it is of fundamental importance to investi gate mechanisms that trigger oscillations in neutron stars in order to char acterize the emitted radiation. We present results from a numerical study o f the even-parity gravitational radiation generated from a particle orbitin g a neutron star. In contrast to previous calculations performed in the Fou rier domain, we use the direct time evolution of the perturbation equations . We focus our investigation on those conditions on the orbital parameters that favor the excitation of w modes. We fmd that for astrophysically reali stic conditions, there is practically no w-mode contribution to the emitted radiation. Only for particles with ultrarelativistic orbital speeds greate r than or equal to0.9c does the w-mode significantly contribute to the tota l emitted gravitational energy. We also stress the importance of setting co nsistent initial configurations.