Spitzer's view of NGC2264's circumstellar disk population

We present a Spitzer study of the pre-main sequence population of the young cluster NGC2264. The disk population is divided into three classes, based on individual spectral energy distributions: optically thick disks, in a homologous manner depleted or anemic disks, and radially depleted transition disks. Our analysis indicated that there may be two distinct evolutionary paths; disks evolve from optically thick to anemic via the first path, and from optically thick to transition in the second. Most of the disks seem to follow the first path. It is yet unknown what physical mechanism triggers this evolutionary differentiation - it could be directly connected to the nature of planet formation within the disk.