RR Lyrae variables in ESO294-G010 and ESO410-G005

In the case of both galaxies, the shapes of the RRL MDFs are well described by pre-enrichment models. This suggests two possible channels for the early chemical evolution for these Sculptor group dTrans galaxies: (1) the ancient stellar populations of our target dwarf galaxies might have formed from the star forming gas which was already enriched through "prompt initial enrichment" or an "initial nucleosynthetic spike" from the very first massive stars, or (2) this pre-enrichment state might have been achieved by the end products from more evolved systems of their nearest neighbor, NGC 55.

We also study the environmental effects of the formation and evolution of our target dTrans galaxies by comparing their properties with those of 79 volume limited (D_{sun}_<2Mpc) dwarf galaxy samples in terms of the luminosity-metallicity relation and the H I gas content. The presence of these RRL stars strongly supports the idea that although the Sculptor Group galaxies have a considerably different environment from the Local Group (e.g., no giant host galaxies, loosely bound and very low local density), they share a common epoch of early star formation with the dwarf satellite galaxies in the Local Group.