Protoplanetary Disk

Protoplanetary disks are rotating disks of gas and dust surrounding young stars, the sites where planets form. These disks are not passive reservoirs of material but active dynamical systems, with gaps, rings, and spiral structures sculpted by planet-disk interactions, photoevaporation, and dust coagulation. ALMA's high-resolution images of disks like HL Tauri have transformed planet formation from a theoretical discipline into an observational one, revealing that planetary architectures begin to emerge while the host star is still accreting. The chemistry of these disks — the distribution of water, organic molecules, and refractory materials — determines the composition of the planetesimals that coalesce within them, making protoplanetary disks the cradle of both worlds and potentially life.