| Full text | |
| Author(s): |
Ortiz, R.
;
Lorenz-Martins, S.
;
Rangel, E. M.
;
Maciel, W. J.
[4]
Total Authors: 4
|
| Document type: | Journal article |
| Source: | Astronomy & Astrophysics; v. 431, n. 2, p. 565-574, 2005. |
| Field of knowledge: | Physical Sciences and Mathematics - Astronomy |
| Location: | ARQUIVO FAPESP |
| Abstract | |
We investigate the evolution of oxygen- and carbon-rich AGB stars, post-AGB objects, and planetary nebulae using data collected mainly from the MSX catalogue. Magnitudes and colour indices are compared with those calculated from a grid of synthetic spectra that describe the post-AGB evolution beginning at the onset of the superwind. We find that carbon stars and OH/IR objects form two distinct sequences in the ( K-[8.3] [8.3]-[14.7]) MSX colour diagram. OH/IR objects are distributed in two groups: the bluest ones are crowded near [14.7]-[ 21.3 and [8.3]-[ 14.7 , and a second, redder group is spread over a large area in the diagram, where post-AGB objects and planetary nebulae are also found. High mass-loss rate OH/IR objects, post-AGB stars, and planetary nebulae share the same region in the ( K-[8.3] [8.3]-[14.7]) and [14.7]-[ 21.3 [8.3]-[14.7]) colour-colour diagrams. This region in the diagram is clearly separated from a bluer one where most OH/IR stars are found. We use a grid of models of post-AGB evolution, which are compared with the data. The gap in the colour-colour diagrams is interpreted as the result of the rapid trajectory in the diagram of the stars that have just left the AGB. (AU) | |
| FAPESP's process: | 02/08816-5 - Photoionized nebulae, stars and the chemical evolution of galaxies |
| Grantee: | Walter Junqueira Maciel |
| Support Opportunities: | Research Projects - Thematic Grants |