Lorentz acceleration (wavy solid gray line) estimated by assuming the solar wind model with an asymptotic speed of 400 km s ⁻¹ and using an empirical relation for drag coefficient. The accelerations due to gravitation ( g: monotonously decreasing dash-dotted red line), drag ( a _d : wavy dotted blue line), and net acceleration from Figure  8 ( a _n : wavy dashed line) are also shown.