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We used Spitzer's Infrared Spectrograph (IRS) to observe stars in the SmallMagellanic Cloud (SMC) selected from the Midcourse Space Experiment (MSX) PointSource Catalog. We concentrate on the dust properties of oxygen-rich evolvedstars, which show less alumina than Galactic stars. This difference may arisefrom the SMC's lower metallicity, but it could be a selection effect: the SMCsample includes more stars which are brighter and thus more massive. Thedistribution of SMC stars along the silicate sequence looks more like that ofGalactic red supergiants than asymptotic giant branch stars (AGBs). While manyare definitively AGBs, several SMC stars show evidence of hot bottom burning.Other sources show mixed chemistry (oxygen-rich and carbon-rich features),including supergiants with PAH emission. MSX SMC 134 may be the first confirmedsilicate/carbon star in the SMC, and MSX SMC 049 is a post-AGB candidate. MSXSMC 145, previously a candidate OH/IR star, is actually an AGB star with abackground galaxy at z=0.16 along the same line-of-sight. We consider theoverall characteristics of all the {\em MSX} sources, the most infrared-brightobjects in the SMC, in light of {\em Spitzer}'s higher sensitivity andresolution, and compare them with the object types expected from the originalselection criteria. This population represents what will be seen in moredistant galaxies by the James Webb Space Telescope (JWST). Color-color diagramsusing the IRS spectra and JWST mid-infrared filters show how one can separateevolved stars from young stellar objects (YSOs) and distinguish among differentYSO classes.

Characterizing the Population of Bright Infrared Sources in the Small Magellanic Cloud