### On the motion of a body in thermal equilibrium immersed in a perfect gas

We consider a body immersed in a perfect gas and moving under the action of a constant force. Body and gas are in thermal equilibrium. We assume a stochastic interaction body/medium: when a particle of the medium hits the body, it is absorbed and immediately re-emitted with a Maxwellian distribution. This system gives rise to a microscopic model of friction. We study the approach of the body velocity to the limiting velocity ${V}_{\infty}$ and prove that, under suitable smallness assumptions, the approach...