Radiation-pressure blowout threshold
= Radiation-pressure blowout threshold
{title2=$\beta=1/2$}
The zero-kick circular-parent threshold is $\beta=1/2$: below it grains are initially bound, at it their conservative release orbit is parabolic, and above it they are initially unbound. <Poynting–Robertson drag> can modify a marginal orbit, so the threshold is a statement about the instantaneous release orbit, not an exact capture criterion with dissipation included.