The Morphologies of the Small Magellanic Cloud

We compare the distribution of stars of different spectral types, and hencemean age, within the central SMC and find that the asymmetric structures arealmost exclusively composed of young main sequence stars. Because of therelative lack of older stars in these features, and the extremely regulardistribution of red giant and clump stars in the SMC central body, we concludethat tides alone are not responsible for the irregular appearance of thecentral SMC. The dominant physical mechanism in determining the current-dayappearance of the SMC must be star formation triggered by a hydrodynamicinteraction between gaseous components. These results extend the results ofpopulation studies (cf. Gardiner and Hatzidimitriou) inward in radius and alsoconfirm the suggestion of the spheroidal nature of the central SMC based onkinematic arguments (Dopita et al; Hardy, Suntzeff & Azzopardi). Finally, wefind no evidence in the underlying older stellar population for a ``bar'' or``outer arm'', again supporting our classification of the central SMC as aspheroidal body with highly irregular recent star formation.