Introduction

An exciting expected consequence of the presence of MBHs in the centre of many, if not all, galaxies (Kormendy & Gebhardt, 2001; de Zeeuw, 2001) is the possibility for a star to be captured onto a relativistic orbit around the MBH by emission of gravitational radiation. For a source at a distance of a few hundreds of Mpc and a MBH's mass in the range between $10^4$ and $10^7 M_\odot$, the frequency of these waves will enter LISA's range as the orbit shrinks down. If it is not tidally disrupted, the star will eventually find itself on an unstable, plunging orbit and disappear through the BH's horizon.