Fate of observers in circular motion

In Newtonian physics or in general relativity, energy dissipation causes observers moving along circular orbits to slowly spiral towards the source of gravitational field. We show that loss has same effect any theory gravity respecting weak equivalence principle, by exhibiting an intimate relation between a massive test particle and stability its orbit. Ultimately, particles either plunge, are driven minima generalized potential, where they become static. addition, we construct toy metric which displays unbound innermost stable orbit, allowing reach this orbit be expelled away.