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We use Hubble Space Telescope (HST) observations of red clump stars taken aspart of the Small Magellanic Cloud Investigation of Dust and Gas Evolution(SMIDGE) program to measure the average dust extinction curve in a ~ 200 pc x100 pc region in the southwest bar of the Small Magellanic Cloud (SMC). Therich information provided by our 8-band ultra-violet through near-infraredphotometry allows us to model the color-magnitude diagram of the red clumpaccounting for the extinction curve shape, a log-normal distribution of$A_{V}$, and the depth of the stellar distribution along the line of sight. Wemeasure an extinction curve with $R_{475} = A_{475}/(A_{475}-A_{814})$ = 2.65$\pm$ 0.11. This measurement is significantly larger than the equivalent valuesof published Milky Way $R_{V}$ = 3.1 ($R_{475} = 1.83$) and SMC Bar $R_{V}$ =2.74 ($R_{475} = 1.86$) extinction curves. Similar extinction curve offsets inthe Large Magellanic Cloud (LMC) have been interpreted as the effect of largedust grains. We demonstrate that the line-of-sight depth of the SMC (and LMC)introduces an apparent "gray" contribution to the extinction curve inferredfrom the morphology of the red clump. We show that no gray dust component isneeded to explain extinction curve measurements when a full-width half-maxdepth of 10 $\pm$ 2 kpc in the stellar distribution of the SMC (5 $\pm$ 1 kpcfor the LMC) is considered, which agrees with recent studies of MagellanicCloud stellar structure. The results of our work demonstrate the power ofbroad-band HST imaging for simultaneously constraining dust and galacticstructure outside the Milky Way.

The Small Magellanic Cloud Investigation of Dust and Gas Evolution (SMIDGE): The Dust Extinction Curve from Red Clump Stars