Mid-IR continuum in NGC 7027: evidence for the presence of hot amorphous carbon grains

We present a simple empirical model which reproduces the observed mid-1R continuum emission of the planetary nebula NGC 7027. The model includes free-free emission and continuum emission from cold and warm amorphous carbon grains. We have used the laboratory measured properties of amorphous carbon grains. The spectrum is modeled between 2 μm and 1 mm and provides evidence that hot amorphous carbon grains provide the bulk of the mid-I R continuum emission.