2025ApJ...995L..23F

Transiting circumbinary planets (CBPs) are conspicuously rare and entirely absent around stellar binaries with periods ≤7 days. Here we exploit a secular resonance to stimulate the orbit of a CBP into strong, disruptive interactions with the host binary. The process requires no tertiary companion and is triggered when the general relativistic precession of a tightening binary matches the Newtonian precession it induces in its companion planet. Adiabatic capture in this resonance sees the binary draining angular momentum from the CBP's orbit, which grows steadily in eccentricity until destabilization and eventual ejection or engulfment. We map this resonance in phase space and then investigate the dynamical outcomes of encounter in the course of tidally shrinking binaries. With the help of orbit-averaged simulations of a suite of systems, we find that, around tightening binaries, 8 out of 10 CBPs encounter and are captured in the resonance, 3 out of 4 are “destroyed,” and survivors lurk on remote, low transit probability orbits. This suggests that the very process that forms tight binaries effectively clears the region where transiting CBPs could reside.