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We have used Hubble Space Telescope ACS images to generate color-magnitudediagrams that reach below the magnitude of the horizontal branch in theSculptor Group dwarf galaxies ESO294-010 and ESO410-005. In both diagrams bluehorizontal branch stars are unambiguously present, a signature of the existenceof an ancient stellar population whose age is comparable to that of theGalactic halo globular clusters. The result is reinforced by the discovery ofnumerous RR Lyrae variables in both galaxies. The occurrence of these stars inthe first direct confirmation of the existence of ancient stellar populationsbeyond the Local Group and indicates that star formation can occur at theearliest epochs even in low density environments.

Ancient stars beyond the Local Group: RR Lyrae variables and Blue Horizontal Branch stars in Sculptor Group Dwarf Galaxies