Tidal and tidal-resonant effects in coalescing binaries

Tidal and tidal-resonant effects in coalescing compact binary systems are investigated by direct numerical integration of the equations of motion. Polytropic models are used for the stars. The tidal effects are found to be dominated by the (non-resonant) f modes. The effect of the g-mode tidal resonances is obtained. The tidal interaction is shown to be of particular interest in the case of low-mass binaries. There exists a characteristic final plunge orbit beyond which the system cannot remain stable even if radiation reaction is not taken into account, in agreement with results obtained by Lai et al. The importance of the investigated effects for the observations of gravitational waves on Earth is discussed.