  A theoretical framework for the determination of tidally induced
radial-velocity variations in a component of a close binary is presented. Both
the free and the forced oscillations of the component are treated as linear,
isentropic perturbations of a spherically symmetric star. Resonances between
dynamic tides and free oscillation modes are taken into account by means of the
formalism developed by Smeyers et al. (1998). The amplitude of the tidally
induced radial-velocity variations seen by the observer depends on the orbital
eccentricity and on the orbital inclination. The amplitude increases with
increasing orbital eccentricity and is most sensitive to the value of the
orbital inclination when 20 < i < 70. In the case of a 5 solar mass ZAMS star
with a 1.4 solar mass compact companion, it is shown that resonant dynamic
tides can lead to radial-velocity variations with amplitudes large enough to be
detected in observations. The shape of the tidally induced radial-velocity
curves varies from very irregular for orbital periods away from any resonances
with free oscillation modes to sinusoidal for orbital periods close to a
resonance with a free oscillation mode. Our investigation is concluded with an
application to the slowly pulsating B star HD 177863 showing the possibility of
resonant excitation of a high-order second-degree g-mode in this star.

Astrophysics