Program: GN-2007B-Q-48

We propose to make a detailed phenomenological study of the UIR bands in the 3-4um and 7-13um intervals, in bright planetary nebulae with simple geometries. The data will allow study of not only the variation in the flux ratios of different bands, but also changes in the spectral shapes of individual bands, in both cases on sub-arcsecond scales. The spectra will allow us to determine the spatial behavior of the bands in each object, determine if there are common trends from object to object, and provide information that laboratory and theoretical astrophysicists and astrochemists can use to understand and interpret these ubiquitous features. Making spatial studies of the UIR bands within individual extended objects is a powerful alternative to observing source-to-source variations, and is now possible in bright compact objects with simple geometries due to the high angular resolution and high sensitivity of Gemini and its instruments. (This proposal is an update/improvement of the proposal for the current program, GN-2007B-Q-78, which was awarded Band 3 status for 2007A. It takes into account the comments of the TAC. As the targets are only available late in 2007A and early 2007B, we will not know until June-July whether any of them have been observed.)