Temperature evolution for disks that include a luminosity outburst of 1000 L_⊙. Both cases have an initial disk radius of 20 AU. Panel a shows a disk that includes viscous heating, and panel b shows a disk that only has heating from irradiation. In the disk of theOutburst model (panel a), the sublimation lines move slowly inward due to the contribution from viscous heating, which eventually decreases, but the material in the inner disk of the Outburst-NoVisc model (panel b) is too cold for the silicate lines to be present.