Development of the lambda2200 extinction feature in posteruptive novae

We describe the changes in the lambda2200 graphite feature that might be expected to occur in classical novae during the posteruptive period. Four models are considered, including the rapid grain formation model of Clayton and Wickramasinghe, and three variants of the preexisting grain model of Bode and Evans. Our results suggest that these models could easily be distinguished using the IUE satellite or similar facility, and that the detailed form of the lambda2200 feature could be an accurate guide to grain size in circumstellar shells. The models developed have applications to a wide variety of objects, including the dust-forming Wolf-Rayet star HD 193793, carbon stars, and T Tauri stars