Dust production rate of asymptotic giant branch stars in the Magellanic Clouds

Abstract

We compare theoretical dust yields for stars with masses 1 ≤ mstar ≤ 8 M⊙ and metallicities 0.001 ≤ Z ≤ 0.008 with observed dust production rates (DPRs) using carbon-rich and oxygen-rich asymptotic giant branch (C-AGB and O-AGB) stars in the Large and Small Magellanic Clouds (LMC and SMC). The measured DPR of C-AGB stars in the LMC are reproduced only if the mass loss from AGB stars is very efficient during the carbon-star stage. The same yields overpredict the observed DPR in the SMC, suggesting a stronger metallicity dependence of the mass-loss rates during the carbon-star stage. The DPRs of O-AGB stars suggest that rapid silicate dust enrichment occurs as a result of efficient hot bottom burning if mstar ≥ 3 M⊙ and Z ≥ 0.001. When compared to the most recent observations, our models support a stellar origin for the existing dust mass, if no significant destruction in the interstellar medium occurs, with a contribution from AGB stars of 70 per cent in the LMC and 15 per cent in the SMC.