A model for particle propulsion by an instantaneous heat discharge is presented. The flow is driven by a gravity-independent transient fluid dilatation, engendered by an unsteady temperature field which corresponds to heat emission from a localized source located within the particle. We focus on the highly eccentric case, where the heat is released in proximity to the particle surface. Solution of the Stokes equations and subsequent evaluation of the resulting hydrodynamic thrust yields a nonlinear non-autonomous ordinary differential equation governing the evolution of particle position with time. This equation depends upon a single parameter which represents the relative effects of heating magnitude and initial geometry.