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| Paper: |
Dust Formation in Oxygen-rich Environments Under Oscillating Thermodynamic Conditions |
| Volume: |
135, A Half Century of Stellar Pulsation Interpretations: a Tribute to Arthur N. Cox |
| Page: |
335 |
| Authors: |
Jeong, K. S.; Winters, J. M.; Fleischer, A. J.; Sedlmayr, E. |
| Abstract: |
We present first results of our work on modelling circumstellar dust shells (CDS) around oxygen--rich long--period variables (LPVs). We consider a gas element which is subject to periodic variations of temperature and density in order to simulate the varying conditions encountered by a gas element moving through the circumstellar shell of a typical oxygen--rich LPV. Assuming chemical equilibrium in the gas phase, we describe the nucleation process of the seed particles by (modified) classical nucleation theory. The nucleating monomers are SiO, Fe, Al2O3, TiO and TiO2, which grow by addition of those molecular species which have a stable solid phase under the local thermodynamic conditions prevailing in the circumstellar environment. Heterogeneous growth of the particles and thermal evaporation are treated by means of a moment method. We discuss the structure and chemical composition of the resulting grains and follow in detail their temporal evolution. |
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