  Transporting solids of different sizes is an essential process in the
evolution of protoplanetary disks and planet formation. Large solids are
supposed to drift inward; high-temperature minerals found in comets are assumed
to have been transported outward. From low-gravity experiments on parabolic
flights we studied the light-induced erosion of dusty bodies caused by a
solid-state greenhouse effect and photophoresis within a dust bed's upper
layers. The gravity levels studied were 0.16g, 0.38g, 1g, and 1.7g. The light
flux during the experiments was 12 +/- 2 kW/m^2 and the ambient pressure was 6
+/- 0.9 mbar. Light-induced erosion is strongly gravity dependent, which is in
agreement with a developed model. In particular for small dusty bodies
((sub)-planetesimals), efficient erosion is possible at the optically thin
inner edges of protoplanetary disks. Light-induced erosion prevents significant
parts of a larger body from moving too close to the host star and be being
subsequently accreted. The small dust produced continues to be subject to
photophoresis and is partially transported upward and outward over the surface
of the disk; the resulting small dust particles observed over the disk's
lifetime. The fraction of eroded dust participates in subsequent cycles of
growth during planetesimal formation. Another fraction of dust might be
collected by a body of planetary size if this body is already present close to
the disk edge. Either way, light induced erosion is an efficient recycling
process in protoplanetary disks.
