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| Paper: |
Dilation of the Cat's Eye |
| Volume: |
313, Asymmetrical Planetary Nebulae III |
| Page: |
155 |
| Authors: |
Balick, B.; Hajian, A.R. |
| Abstract: |
WFPC2 images of NGC 6543 obtained in 1994.7 and 2000.7 reveal the detailed structure and growth patterns of its core. Subtracting the [O III] and [N II] images shows a pattern of expansion that clearly departs from uniform growth. Surface brightness changes that vary from feature to feature are found, with increases of [O III] of up to 3% and decreases of [N II] of 7 - 9%. We find expansion age of ~1300 y for the innermost structure E25 and ~1500 y for most of the outer features assuming ballistic motions. However, the sharply defined edges and features suggest that hydrodynamic shaping is (or has recently) been important. The most commonly accepted application of hydrodynamics to the growth of planetary nebulae is the paradigm of "Interacting Stellar Winds" (ISW). The growth of E25 can be successfully understood within the ISW framework; however there are serious problems when ISW is applied to all of the other features. |
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