Introduction to Classical Mechanics · Problem 7.13
Angular momentum, Part I (Constant L) — Morin
Physics — Mechanics · gravity-kepler-laws
Problem
Intersecting orbits **
Two masses, m and 2m, orbit around their CM. If the orbits are circular, they don't intersect. But if they are very elliptical, they do. What is the smallest value of the eccentricity for which they intersect?