  We perform a simulation using the Astrophysical Multipurpose Software
Environment of the Orion Trapezium star cluster in which the evolution of the
stars and the dynamics of planetary systems are taken into account. The initial
conditions from earlier simulations were selected in which the size and mass
distributions of the observed circumstellar disks in this cluster are
satisfactorily reproduced. Four, five, or size planets per star were introduced
in orbit around the 500 solar-like stars with a maximum orbital separation of
400au. Our study focuses on the production of free-floating planets. A total of
357 become unbound from a total of 2522 planets in the initial conditions of
the simulation. Of these, 281 leave the cluster within the crossing timescale
of the star cluster; the others remain bound to the cluster as free-floating
intra-cluster planets. Five of these free-floating intra-cluster planets are
captured at a later time by another star. The two main mechanisms by which
planets are lost from their host star, ejection upon a strong encounter with
another star or internal planetary scattering, drive the evaporation
independent of planet mass of orbital separation at birth. The effect of small
perturbations due to slow changes in the cluster potential are important for
the evolution of planetary systems. In addition, the probability of a star to
lose a planet is independent of the planet mass and independent of its initial
orbital separation. As a consequence, the mass distribution of free-floating
planets indistinguishable from the mass distribution of planets bound to their
host star.
