Carbon Stars and Dust
Event date
Gregory Sloan
Event Type

Carbon stars dominate the observed production of dust in nearby metal-poor dwarf galaxies. To understand the chemical enrichment history and dust budgets of those galaxies, we must understandn the carbon stars. Infrared spectra from the Spitzer Space Telescope have shown that carbon stars form and dredge up enough of their own carbon to produce significant amounts of dust, no matter their initial metallicity. Photometric surveys from Spitzer, combined with FORCAST spectra from SOFIA, have revealed a dichotomy in the dust they produce, with both the quantity and chemistry of the dust dependent on the star's pulsations. SOFIA spectra of Galactic carbon stars show that weakly pulsating carbon stars produce small amounts of SiC and little more, while strong pulsators produce large quantities of amorphous carbon. The pulsations and dust production grow in intensity until the star has ejected its envelope and begins to evolve into a planetary nebula.

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