Star Formation in the Small Magellanic Cloud: The Sparkling Nurseries NGC 346 and NGC 02

Elena Sabbi

The question of how the combination of metallicity and dust content can impact the star formation process has profound implications for our understanding of how stars formed in the early universe. The Small Magellanic Cloud (SMC) is an ideal empirical laboratory for this research, due to its sub-solar metallicity (Z = 0.004) and its low dust content (30 times lower than in our Galaxy). In addition, its close proximity allows us to perform a detailed and accurate census of its stellar content.

In 2004 we started a deep ACS/HST survey of the SMC, with the objective of deriving the most detailed and accurate star formation history of this galaxy as a function of spatial position. Here we will present the two young star forming regions NGC 346 and NGC 602.

The clusters are located in the bar and the bridge of the SMC respectively, and have different masses and regimes of star formation. In both clusters we have found rich populations of pre-Main Sequence stars, in the mass range 3 to 0.6 solar masses. These two clusters are still dipped in ionized gas and molecular clouds, and show Bok globes, pillars, and star clusters embedded in dust, suggesting the presence of a second stellar generation. We will present the photometric results, the luminosity and the mass functions, the role of massive star feedback, and the star formation histories of the analyzed regions, and we will discuss the implications of our results in the context of star formation in low metallicity environments.