Bibcode
Manchado, A.; García-Hernández, D. Anibal; Villaver, Eva; de Massas, Jean Guironnet
Referencia bibliográfica
Planetary Nebulae: An Eye to the Future, Proceedings of the International Astronomical Union, IAU Symposium, Volume 283, p. 83-86
Fecha de publicación:
8
2012
Número de citas
1
Número de citas referidas
1
Descripción
We present a complete study of the morphology of post-Asymptotic Giant
Branch (post-AGB) stars. The post-AGB stage is a very short evolutionary
phase between the end of the AGB and the beginning of the Planetary
Nebula (PN) stage (between 100 and 10,000 yrs). Post-AGB stars do not
show variability and are not hot enough to fully ionize the hydrogen
envelope. We have defined the end of the post-AGB phase and the
beginning of the PN phase when the star has a temperature of 30000 K.
Post-AGB stars have a circumstellar shell that is illuminated by the
central stars or partially ionized. However, this circumstellar shell is
too small to be resolved by ground-based observations. Thus, we have
used the Hubble Space Telescope (HST) database to resolve these shells.
117 post-AGBs were found in this database. Here we present the
preliminary results on their morphological classification and the
correlation with the galactic latitude. Our preliminary results show
that 38% of the sample are stellar-like (S), 31% bipolar (B), 12%
multipolar (M) and 19% elliptical (E).