Abstract details

As a part of the large cycle 14 HST/ACS program 'The onset of star formation in the Universe: Constraints from Nearby Isolated Dwarf Galaxies', we obtained very deep (V~28) multi-epoch images of the dSph Tucana and the so-called transition dSph/dIrr LGS3. We present the first results of the search for short-period variable stars in these two galaxies: classical and anomalous cepheids, and RR Lyrae. We discuss the characteristics of the stellar populations they represent. The results will be interpreted in the context of the star formation history of these galaxies.