Life cycle of dust in the Magellanic Clouds and the Milky Way

Abstract

To a great extent, our understanding of the life cycle of dust is based on the observational and theoretical studies of the Milky Way and the Magellanic Clouds, which will be the topic of this contribution. Over past years, a large volume of observations with unprecedented spatial resolution has been accumulated for the Milky Way. It permits investigations of different stages of the life cycle of dust, from its formation in stellar sources to destruction in star-forming regions and supernovae shocks. Observations of dust emission, extinction, and interstellar element depletions in the solar neighbourhood yield the most accurate constraints for interstellar dust models providing a reference for studies of dust content in extragalactic systems. However, global spatial studies of the circumstellar and interstellar dust are complicated in the Milky Way disk because of high extinction, confusion along the line of sight and large uncertainties in distances. In contrast, the favourable location in the sky and the proximity of the Magellanic Clouds allow detailed multi-wavelength studies of the dust-forming stellar populations and the investigation of variations of the interstellar grain properties for the entire galaxies. They enable the first comparison between the global stardust production rates from theoretical calculations and those from observations, which confirm discrepancy between accumulated stardust mass and observed interstellar dust mass - "the missing dust-source" problem. Modelling of the life cycle of dust in the Large Magellanic Cloud showed that dust growth by mantle accretion in the ISM, a major dust source in the Milky Way, can also be responsible for the existing dust mass in the LMC. We will present comparison of the dust input from different sources to the dust budgets of the Milky Way and the Magellanic Clouds, which reveals how the role of these dust sources depends on metallicity.