FLIERs as stagnation knots from partially collimated outflows
Abstract
We propose a new model for the formation of fast, low-ionization emission regions (FLIERs) in planetary nebulae that is able to account for many of their attendant characteristics and circumvent the problems on the collimation/formation mechanisms found in previous studies. In this model, FLIERs are formed in the stagnation zone of partially collimated stellar winds with reduced momentum flow along the axis. A concave bow-shock structure is formed due to the lack of momentum flow along the axis of a midly bipolar stellar wind. The stagnation knots are formed when the shocked environment medium accumulates at the apex of the outer shell and is compressed to a dense knot in the {\em concave} section of the bow-shock. We present two-dimensional hydrodynamic simulations of the formation of a stagnation knot and compare the resultant dynamical properties with those of FLIERs in planetary nebulae.
Keywords
Cite
@article{arxiv.astro-ph/9909261,
title = {FLIERs as stagnation knots from partially collimated outflows},
author = {Wolfgang Steffen and Jose Alberto Lopez},
journal= {arXiv preprint arXiv:astro-ph/9909261},
year = {2007}
}
Comments
4 pages incl. 1 fig., to be published in the proceedings of the conference on Asymmetrical Planetary Nebulae II, PASP Conference Series, 2000, J.H. Kastner, N. Soker, S. Rappaport, eds