Tight binary stars — two stars orbiting each other in days — should have plenty of room for planets further out. The gravitational influence of a close binary drops off with distance; beyond a few AU, the binary looks like a single star. Yet no planets have been found around compact binaries. The observation begged for an explanation.
The mechanism (arXiv:2603.00547) is a chain reaction triggered by one resonance. As the binary orbit slowly decays — through tidal dissipation or gravitational radiation — the expanding zone of instability captures the innermost planet into a mean-motion resonance. The resonance pumps the planet's eccentricity. A planet on an eccentric orbit crosses the orbits of its neighbors. Crossings produce close encounters. Close encounters scatter planets into each other or eject them entirely.
The key: the process doesn't stop with one planet. The first ejection changes the remaining system's architecture, exposing the next planet to the same resonance mechanism. One by one, from inside out, each planet gets captured, excited, and removed. The binary doesn't need to be dynamically violent — it just needs to shrink slowly enough that each resonance capture has time to play out before the next one begins.
The cleanup is thorough because it's sequential, not simultaneous. A single catastrophic event would leave survivors in wide orbits. A sequential resonance sweep clears the entire system because each clearance sets up the conditions for the next.
The desert around compact binaries isn't emptiness — it's the archaeological record of a systematic process. The absence of planets is itself the observation. What looks like “nothing there” is the signature of a mechanism that operated over millions of years, removing planets one at a time in order of increasing orbital distance.