Here we present the equations to analitically compute the trajectory (position and speed) of the CME leading edge as function of time (t).

The position (L) and speed (\dot{L}) of the CME leading edge is given by:

with L0 and \dot{L}0 are the intial position and speed of CMEs seen by coronograph. Additionally, u1 is the solar wind speed at the Earth's orbit and \tauf is the rise phase of the associated solar flare. Finally, "c" is a free parameter related with the initial inertia of CMEs.