Temperature structure of the disk as a function of distance from the central star. The solid red, brown, and orange lines correspond to the initial temperature profiles using viscosities of 10⁻², 10⁻³, and 10⁻⁴, respectively. The solid black line is a power-law temperature profile that remains static, chosen to match the outer disk temperature of a passively heated disk. The dashed and dotted lines show the evolution of the temperature at 0, 10⁶, and 3 × 10⁶ years.