| |
 |
| Paper: |
Polar Outflows in PNe |
| Volume: |
313, Asymmetrical Planetary Nebulae III |
| Page: |
161 |
| Authors: |
Lopez, J.A.; Garcia-Segura, G.; Steffen, W. |
| Abstract: |
Planetary nebulae show axi-symmetric outflows with a wide range of characterstics. Symmetry is defined with respect to the central star and the outflows define a symmetry axis that is assumed to coincide with the stellar polar axis. However, the increasingly complex morphologies found recently seem to challenge in some instances the traditional interpretation of simple polar outflows in PNe. This work presents a brief review of the characteristics of symmetric outflows that are found in PNe and the current models that attempt to explain their origin. Instead of discussing the latest observations in the field, this work takes the alternative view of going back to the early prototypical objects that sparked the current research on collimated outflows in PNe. The reason for doing this is simple, many of the fundamental questions raised by those early observations remain unanswered today, although tremendous progress in the understanding, and confirmation, of several related phenomena has undoubtedly been achieved in recent times. |
|
|
|
|
|
