Comparison of the simulated breaking radius to analytical predictions. Top: Analytical time-scales as predicted from equations (12) and (13). Here, |$r_{\rm {in}}$| is calculated to be |$2.2a_{\rm b}$| (see text for details). Bottom: Surface density of the |$\alpha = 10^{-5}$| simulation at |$t = 100$| binary orbits, in units of the initial surface density profile |$\Sigma _0$|⁠. The breaking radius is denoted by the sharp dip in |$\Sigma /\Sigma _0$|⁠. In both plots, vertical dashed lines indicate the predicted locations of the breaking radius.