Temperatures in protoplanetary disks

Observations of suspected planet-forming disks provide estimates of protoplanetary disk masses, surface temperatures, and the rate at which mass is infalling onto the disks. Analyses of primitive meteorites and comets and their components constrain the solar nebula's temperature at the locations and times where those components were formed. Theoretical models of disks undergoing the accretion of mass from an infalling cloud envelope predict disk temperatures in good agreement with these constraints: a moderately warm (500-1500 K) inner disk, surrounded by a cool (50-150 K) outer disk. These models have important implications for the depletion of volatiles in the inner Solar System, for mechanisms of disk evolution, and for the orbital distances at which terrestrial and gas giant planets form.