A rocky road from dust to planets / Dr Min-Kai Lin (ASIAA)

Planets appears commonplace in the Universe. However, the details of their formation 
remains a puzzle. The building blocks of planets are planetesimals, themselves formed 
from small dust grains immersed in a gaseous protoplanetary disk (PPD) surrounding 
young stars. Thus, understanding the dust-gas dynamics in PPDs lays the foundation to 
any theory of planet formation. I will present recent work on dust-gas dynamics in PPDs 
and discuss implications for planet formation. I first describe the problem of dust 
sedimentation in PPDs. This process is widely considered as a necessary step towards 
planetesimal formation. However, turbulence in the disk can stir up dust particles, 
thereby prevent planetesimal formation. I will discuss how dust can overcome turbulence 
and sediment by accounting for two-way drag forces between gas and dust. I will then 
describe how newly born protoplanets continue to interact with its surrounding disk. 
Such disk-planet interactions may be responsible for substructures such as rings and 
gaps now commonly observed in real PPDs. I show that planets interacting with a dusty 
disk can differ significantly from the more frequently studied case of pure gas disks. 
This may be important for shaping the final architecture of planetary systems. Finally, 
I will give a preview of upcoming projects that combine disk-planet interaction and 
dust settling in the context of PPD substructures.