Dust Formation in the Ejecta of Common Envelope Systems

The material that is ejected in a common-envelope (CE) phase in a close binary system provides an ideal environment for dust formation. By constructing a simple toy model to describe the evolution of the density and the temperature of CE ejecta and using the \emph{AGBDUST} code to model dust formation, we show that dust can form efficiently in this environment. The actual dust masses produced in the CE ejecta depend strongly on their temperature and density evolution. We estimate the total dust masses produced by CE evolution by means of a population synthesis code and show that, compared to dust production in AGB stars, the dust produced in CE ejecta may be quite significant and could even dominate under certain circumstances.