Registry · Theorem
V.T82
tau-effective
formalized
V.T82 — Kepler's First Law --- V.T34
In the classical regime (all three Newtonian-limit conditions satisfied), every bound orbit of a test particle around a central mass M is a conic section; for negative total energy, the orbit is an ellipse r(theta) = a(1-e^2)/(1+e cos theta).