Class II and III disks with Gaia and ALMA data

We propose a new evolutionary scenario wherein radial drift is very efficient for nonstructured disks during the Class II phase resulting in a rapid Mdust decrease. In addition, we find possible evidence for long infrared protoplanetary disk timescales, ~8Myr, consistent with overall slow disk evolution. In structured disks, the presence of dust traps allows for the formation of planetesimal belts at large radii, such as those observed in debris disks.

We propose therefore that the planetesimal belts in debris disks are the result of dust traps in structured disks, whereas protoplanetary disks without dust traps decrease in dust mass through radial drift and are therefore undetectable as debris disks after the gas dissipation. These results provide a hypothesis for a novel view of disk evolution.