Histogram of the disk integrated C¹⁸O luminosities of models run by the thermochemical code DALI for three different disk masses, as indicated in the top-left of each panel. A comparison is done between the models used by S24 (gray), and models for which the stellar effective temperature has been lowered to an IMTT appropriate value either with (red) or without (blue) accretion UV added. The lower effective temperature of the IMTT star increases the C¹⁸O luminosity for the lowest mass disks compared to the Herbig disk models, as there is less UV emission and therefore less photodissociation of CO. Adding the accretion UV increases the photodissociation of CO, moving the C¹⁸O luminosity back to Herbig disk levels.