These come from the fact that for small values of b~ and μ, as considered here, Eqs.(2・1) and (2.2) are approximately symmetric with respect to the y-axis.
Now, we will see features of collision of a particle with the planet. It should be noticed that, as mentioned in §2, the radius of the planet changes with the distance between the Sun and the planet is assigned. Here we will concentrate on the collision near the orbit of the present Earth.
よろしくお願いします。
お礼
どうもありがとうございました。 §2は2章ということだと思われます。