The Influence of Ice Lines on Dust Growth

Ice lines are special locations in protoplanetary disks at which a phase transition between the solid and the gaseous phase of 
a volatile species occurs. Ice lines are of special interest in planetary sciences since they have a direct influence on the 
coagulation physics of colliding dust particles.
Dust particles that are drifting inwards through ice lines lose their volatiles through evaporation. This newly created vapour 
can diffuse backwards through the ice line and recondenses there preferentially on small dust particles. This recondensation 
increases the monomer size of the dust aggregates in a region just outside the ice line. A larger monomer size, in turn, leads to a 
smaller fragmentation velocity.
This effect changes the typical particle sizes in these regions of recondensation and creates ringlike, axis-symmetric 
emission features in observations of protoplanetary disks.