Talk abstract details
Morphological classification of post-AGB stars
Abstract
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 data from the Hubble Space Telescope (HST) database to resolve these shells. 140 post-AGBs were found in this database. Here we present the preliminary results on their morphological classification and the correlation with several parameters such as
galactic latitude and 2MASS and IRAS fluxes. Our preliminary results show that 40 \% of the sample
are stellar-like (S), 33 \% bipolar (B), 12 \% multipolar (M) and 15 \% elliptical (E).
(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 data from the Hubble Space Telescope (HST) database to resolve these shells. 140 post-AGBs were found in this database. Here we present the preliminary results on their morphological classification and the correlation with several parameters such as
galactic latitude and 2MASS and IRAS fluxes. Our preliminary results show that 40 \% of the sample
are stellar-like (S), 33 \% bipolar (B), 12 \% multipolar (M) and 15 \% elliptical (E).