Evolution and Dispersal of Protoplanetary Disks.

Multiwavelength studies of evolved protoplanetary disks around solar-type and low-mass stars reveal a general trend of changes in the IR excesses, accretion rates, and silicate features, suggesting grain growth/settling, photoevaporation, and maybe the formation of planetesimals and planets. Nevertheless, within the average-behavior picture of disk evolution, we observe strong variations between individuals, that may be related to different initial conditions, different environments, and the presence of companions. [ABSTRACT FROM AUTHOR]