  We have modeled self-consistently the density and temperature profiles of gas
and dust in protoplanetary disks, taking into account irradiation from a
central star. Making use of this physical structure, we have calculated the
level populations of molecular hydrogen and the line emission from the disks.
As a result, we can reproduce the observed strong line spectra of molecular
hydrogen from protoplanetary disks, both in the ultraviolet (UV) and the
near-infrared, but only if the central star has a strong UV excess radiation.
