  In this paper we consider the Extra-solar Planetary Systems recently
discovered in our Galaxy as potential sources of gravitational waves. We
estimate the frequency and characteristic amplitude of the radiation they emit
due to the orbital motion, using the quadrupole formalism. In addition, we
check whether the conditions needed for the resonant excitation of the f- and
g-modes of the central star can be fulfilled. By a Roche-lobe analysis, we show
that there could exist systems in which the low-order g-modes could be excited,
although this does not happen in the systems discovered up to now.
