Understanding exotic black hole orbits using effective potentials

Abstract

Strongly gravitating systems can undergo unusual orbital trajectories. For example, “extreme mass ratio inspirals” (observable in the megahertz band by space-based gravitational wave detectors) can exhibit “zoom-whirl” orbits, which make complicated waveforms that are useful for mapping out the system's gravitational structure. Zoom-whirl behavior can be intuitively understood in the context of effective potentials, which should be familiar to students from classical orbital theory in mechanics. Here, we explore zoom-whirl orbits using effective potential theory around Schwarzschild black holes and present an interactive tool that can be used in pedagogical settings.