EQUIPOTENTIAL SURFACES IN CLOSE BINARY-SYSTEMS - REMARKS ON THE TIME-DEPENDENT POTENTIAL FUNCTION

By use of the mass-point model, the equations of the equipotential surfaces are reviewed. A difference between the time-dependent potential function and zero relative velocity surfaces is put in evidence. A drawback in the time-dependent transformation between (xi, eta, zeta) and (x, y, z) coordinate systems is underlined.