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| Paper: |
Properties of the Circumstellar Envelope of the Dual Chemistry Post-AGB Star Roberts 22 |
| Volume: |
378, Why Galaxies Care About AGB Stars: Their Importance as Actors and Probes |
| Page: |
295 |
| Authors: |
Epitacio Pereira, D.N.; de Araujo, F.X.; Lorenz-Martins, S.; Ercolano, B.; Barlow, M.J.; Bowey, J.E. |
| Abstract: |
A major discovery by the ISO satellite was the presence, in the spectra of many evolved stars, of an array of narrow emission features that could be attributed to crystalline silicate grains in their envelopes (Molster et al. 2002). As the circumstellar envelope is formed from the continuous mass loss of the object during the AGB stage, it is natural to suppose that the central star would share its chemical properties. Thus, one would expect a star surrounded by silicate-rich material to be oxygen-rich. However, crystalline silicates are frequently associated with carbon-rich central objects. These dual chemistry objects present an opportunity to investigate the mechanisms of mass ejection that forms the circumstellar envelope during and after the AGB stage and that also contribute to the enrichment of the interstellar medium. We are modeling the dust envelope of Roberts 22, a post-AGB star with dual chemistry, using a Monte Carlo simulation method to describe the radiative transfer in its circumstellar dust envelope. |
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