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Paper: |
High Resolution CO Observations of Evolved Stars Imaged with the BIMA Array and Some ISO Results |
Volume: |
199, Asymmetrical Planetary Nebulae II: From Origins to Microstructures |
Page: |
87 |
Authors: |
Fong, David; Meixner, Margaret; Sutton, E. C.; Welch, W. J.; Bujarrabal, ValentÃn; Castro-Carrizo, Arancha |
Abstract: |
We present high resolution CO images and ISO results from 4 objects in our evolved star survey. The CO maps show the elliptical structure of HD 161796, the unusual morphology of IRAS 22272+5435, and the aspherical shape of AFGL 2688. The absence of FIR emission in these PPNe suggests that their asymmetries emerge prior to the onset of shocks or photodissociation, with the exception of AFGL 2688 where shocked H2 gas was previously detected. The PN NGC 7027 shows a bright, circumstellar shell of emission in 12CO. Unlike the PPN sample, rich atomic fine structure lines were also observed there. |
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