Problem 1.207

A planet of mass $m$ moves along an ellipse around the Sun so that its maximum and minimum distances from the Sun are equal to $r_{1}$ and $r_{2}$ respectively. Find the angular momentum $M$ of this planet relative to the centre of the Sun.

M=m \sqrt{2 \gamma m_{s} r_{1} r_{2} /\left(r_{1}+r_{2}\right)},

Universal Gravitation