Unclear duration of dust grain settling in protoplanetary disks

Ascertain the timescale over which dust grains settle in protoplanetary disks, particularly during the transition from Class I to Class II, to better interpret edge-on scattered-light morphologies and vertical dust distributions.

Background

Multiple edge-on disks show signatures of vertical dust stratification, yet the temporal evolution of grain settling is not well constrained. The authors note that DraChi likely lies near the Class I/II transition and adopt a two-population (small and large grains) disk model with different scale heights to simulate settling.

Establishing the duration of grain settling would inform disk evolution models and reduce uncertainties in disk mass estimates, which are sensitive to assumed grain size distributions and opacities.