Dust formation in the winds of low metallities AGBs and implications for cosmic dust enrichment

We have calculated the dust formed around AGB and super-AGB stars of metallicity Z = 3 × 10−4 , the lowest metallicity for which dust production by low and intermediate mass stars has been considered so far. This study complements previous investigations that were limited to metallicities Z = 10−3 and Z=8 × 10−3 . Stellar evolution is followed by means of a full integration of the equations of stellar structure, allowing to describe self–consistently the Hot Bottom Burning phenomenon. Our results imply that at these low initial metallicities, the production of dust is strongly suppressed, suggesting that in cosmic environments with metallicities Z < 5× 10−3 Z dust enrichment is entirely dominated by Supernovae.