Extremely metal-poor stars in classical dwarf spheroidal galaxies:
  Fornax, Sculptor and Sextans
  We present the results of a dedicated search for extremely metal-poor stars
in the Fornax, Sculptor and Sextans dSphs. Five stars were selected from two
earlier VLT/Giraffe and HET/HRS surveys and subsequently followed up at high
spectroscopic resolution with VLT/UVES. All of them turned out to have [Fe/H]
<= -3 and three stars are below [Fe/H] -3.5. This constitutes the first
evidence that the classical dSphs Fornax and Sextans join Sculptor in
containing extremely metal-poor stars and suggests that all of the classical
dSphs contain extremely metal-poor stars. One giant in Sculptor at [Fe/H]=-3.96
+- 0.10 is the most metal-poor star ever observed in an external galaxy. We
carried out a detailed analysis of the chemical abundances of the alpha, iron
peak, and the heavy elements, and we performed a comparison with the Milky Way
halo and the ultra faint dwarf stellar populations. Carbon, barium and
strontium show distinct features characterized by the early stages of galaxy
formation and can constrain the origin of their nucleosynthesis.
