Bibcode
Gonçalves, D. R.; Corradi, R. L. M.; Villaver, E.; Mampaso, A.; Perinotto, M.
Referencia bibliográfica
"Astrophysical Plasmas: Codes, Models, and Observations, Proceedings of the conference held in Mexico City, October 25-29, 1999, Eds. Jane Arthur, Nancy Brickhouse, and José Franco, Revista Mexicana de Astronomía y Astrofísica (Serie de Conferencias), Volume 9, p. 216-219 POSTSCRIPT: http://www.astrosmo.unam.mx/rmaa/APCM/PSGZ/sapcm_goncalves.ps.gz"
Advertised on:
5
2000
Número de citas
0
Número de citas referidas
0
Descripción
In this contribution we discuss new results of a program aimed at
studying the physical properties, origin and evolution of
``low-ionization, small-scale structures in PNe''. Within this project
we classify and discuss the properties of a sample of more than 50 PNe,
collected from the literature, in the light of their possible formation
mechanisms. In addition, we obtained images and spectra for 10 of these
PNe, finding low-ionization structures with very different properties
relative to each other, in terms of expansion velocities, shapes, sizes
and locations relative to the main nebular components. Several physical
processes have to be invoked in order to account for the formation and
evolution of jets and jet-like structures observed. We present here some
results which are illustrative of our work--on IC 4593, NGC 3918, NGC
6337--comparing the different low-ionization structures in these PNe and
illustrating some of the questions that we try to address. The most
interesting result we obtained is that the collimated LIS present a
linear increase in the expansion velocity from inner to outer regions.
This is an important constraint on the models and is, in fact, one of
the predictions of the interacting-stellar-wind models for the formation
of jets, if stellar magnetic fields are considered.