演講資訊

摘要：

Asymptotic giant branch (AGB) stars lose a substantial fraction of their mass in slow, dust-driven winds. This mass loss directly influences the life cycle of dust and gas in galaxies. The dust consists of either oxygen-rich or carbonaceous partiels, depending on the relative atomic abundance of carbon to oxygen (the C/O ratio) in the photospheric regions. Determining the current rate of AGB dust production requires information about the spectral energy distributions (SEDs), especially in the infrared. While large-scale studies of the Galactic AGB dust budget have been restricted to the Bulge or the Solar Neighbourhood, data from the Spitzer Space Telescope has enabled the identification of large AGB populations in nearby galaxies such as the Magellanic Clouds, allowing us to estimate the current AGB dust budget in these systems. These studies find that the dust production is dominated by a small fraction of very dusty, highly evolved stars. However, the global estimates seem too small to explain the observed interstellar dust mass. In this talk, I will review the theoretical and observational constraints on AGB dust production in nearby galaxies and discuss possible solutions to the dust budget "crisis".