Abstract details

We present a quantitative analysis of the star formation history (SFH) of different parts of the Small Magellanic Cloud (SMC) from the information in ground-based {\it B} and {\it R}-band color-magnitude diagrams (CMDs) of unprecedented depth, reaching the oldest main-sequence turnoffs, which allows us to retrieve the SFH in great detail. The method we use is based on comparing the expected distribution of stars in synthetic CMDs for different evolutionary scenarios with the observed distribution. We consider the SFH to be composed by the SFR(t), the chemical enrichment law Z(t), the initial mass function (IMF), and a function $\beta$(f,q) controlling the fraction f and mass ratio distribution q of binary stars. The comparison between the observed and model CMDs is done through $\chi$^2 minimization of the differences in the number of stars in a set of regions of the CMDs, chosen to sample stars of different ages or in specific stellar evolutionary phases.