Hideyuki Saio Simon Jeffery are exploring models for the evolution of stars formed by the merger of two white dwarfs. The attached movie provides a simulation of the major events involved in the merger process. ... An initial binary system consists of two white dwarfs of masses M 1 and M 2 (given) with an orbital period ( P ). ... We adopt a simple expression for the white dwarf radius as a function of mass (in solar units): . ... The merged star evolution is simulated by a quadratic expansion . ...