Abstract <p>We revisit the problem of relaxation in a scalar gravitational field theory proposing a novel numerical solution to the problem. We predict the approach to equilibrium of a spherically symmetric field-particle system initially excited in a non-equilibrium state, where the particle is in an unstable circular orbit around the origin. We explicitly work out a quasistatic approximation in an unstable circular orbit to the exact dynamical problem. Our toy model could give some relevant insights in the full General Relativity realistic model as theoretical effort is carried on to solve it numerically. For example we propose to use the method of images to tackle a numerical solution of the resulting wave equation.</p>