Bibcode
Mampaso, A.
Referencia bibliográfica
Asymmetrical Planetary Nebulae III: Winds, Structure and the Thunderbird, Proceedings of the conference held 28 July - 1 August 2003 at Mt. Rainer, Washington, USA. Edited by Margaret Meixner, Joel H. Kastner, Bruce Balick and Noam Soker. ASP Conference Proceedings, Vol. 313. San Francisco: Astronomical Society of the Pacific, 2004., p.265
Fecha de publicación:
7
2004
Número de citas
2
Número de citas referidas
2
Descripción
Results appearing since the last APN meeting on the relation between
abundances and PNe morphological features are reviewed here. Statistical
analyses of round, elliptical, and bipolar PNe clearly separate the
latter group as having larger He and N/O abundances. Studies of
individual PNe, including the UV and IR domains, allow a detailed
comparison with evolutionary models for the AGB phase; the abundances of
the most important elements can be matched but an `age-metallicity'
problem for the progenitors of He-rich PNe is implied. Halo abundances
do not show strong chemical differences with respect to the PN rims, but
the halos' faintness requires deeper data to confirm it. Data on the
chemistry of microstructures of normal (non H-deficient) PNe are scarce
and generally indicate similar abundances to those in the rims. The
exception is the high nitrogen overabundance claimed for FLIERS;
preliminary modeling on new observational data of the microstructures of
NGC 7009 indicates that a moderate enrichment of nitrogen can be real.