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Colloquium by Ciska Kemper (ASSIA)

The dust production by evolved stars in the Magellanic Clouds

Abstract: Within the context of the hugely successful SAGE-LMC and SAGE-SMC surveys, Spitzer photometry observations of the Large and Small Magellanic Clouds have revealed millions of infrared point sources in each galaxy. The brightest infrared sources are generally dust producing and mass-losing evolved stars, and several tens of thousands of such stars have been classified. After photometrically classifying these objects, the dust production by several kinds of evolved stars -- such as Asymptotic Giant Branch stars and Red Supergiants -- can be determined.  SAGE-Spec is the spectroscopic follow-up to the SAGE-LMC survey, and it has obtained Spitzer-IRS 5-40 micron spectroscopy of about 200 sources in the LMC. Combined with archival data from other programs, observations at a total of ~1000 pointings have been obtained in the LMC, while ~250 IRS pointings were observed in the SMC. Of these, a few hundred pointings represent dust producing and mass-losing evolved stars, covering a range in colors, luminosities, and thus mass-loss rates. Red Supergiants and O-rich and C-rich AGB stars -- the main dust producers -- are well represented in the spectroscopic sample.  In this talk I will review what we know about the mineralogy of dust producing evolved stars, and discuss their relative importance in the total dust budget.

Time: Apr. 22, 2015, 2:30 pm

Venue: A601, NAOC