  The structure and chemistry of protoplanetary disks depends strongly on the
nature of the central star around which it has formed. The dust temperature is
mainly set by the stellar luminosity, while the chemistry of the upper disk
layers depends on the amount of intercepted UV and X-ray flux. We will study
the differences in chemistry, thermal sturcture and line emission around Herbig
Ae/Be, T Tauri stars and low mass M dwarfs. Predictions will be made for future
observations with SOFIA and Herschel.
