Near-resonant transit-timing superperiod
= Near-resonant transit-timing superperiod
{title2=$P_t=2\pi/|(j+1)n_2-jn_1|$}
For two nearly circular <Kepler orbits> near a first-order $(j+1):j$ period ratio, the slow <resonant argument> circulates on the displayed superperiod when <longitude of periapsis> precession is negligible. If $P_2/P_1=((j+1)/j)(1+\Delta)$, then $P_t=P_1(1+\Delta)/(j|\Delta|)$. Within <resonant-argument libration>, this circulation formula is replaced by an amplitude-dependent libration period.