Protostars and Planets VI, Heidelberg, July 15-20, 2013
LMC: Dust Input from AGB stars at sub-solar metallicities
Zhukovska, Svitlana (Max-Planck-Institut für Astronomie; Zentrum für Astronomie, Institut für Theoretische Astrophysik, Universität Heidelberg)
Henning, Thomas (Max-Planck-Institut für Astronomie)
The dust-forming population of AGB stars and their input to the interstellar dust budget of the Large Magellanic Cloud (LMC) are studied with evolutionary dust models with the main goals (1) to investigate how the amount and composition of dust from AGB stars vary over the galactic history; (2) to characterise the mass and metallicity distribution of the present population of AGB stars; (3) to quantify the contribution of AGB stars of different mass and metallicity to the present stardust population in the ISM. For the first time, theoretically calculated dust production rates of AGB stars are compared with those derived from infrared observations of AGB stars for the entire galaxy. We show that the majority of silicate and iron grains in the present stardust population originate from a small population of intermediate-mass stars consisting of only 4% of the total number of stars, whereas in the solar neighbourhood the parent stars have bimodal mass distribution with a large contribution from low-mass stars. With models of the lifecycle of stardust grains in the LMC, we confirm the strong discrepancy between dust input from stars and the existing interstellar dust mass in the LMC.
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