Eccentricity, semimajor axis, and surface temperature evolution for the 1500 planetesimals in the nominal HL Tau simulation, produced in a similar manner as Fig. 1. The solid black lines mark the perihelia of the planets. Many planetesimals end up in the scattered disks of the planets, where they obtain high eccentricities. Only planetesimals scattered tointerior of the innermost planet’s orbit obtain perihelion temperatures large enough for ablation to take place.