Bibcode
Tafelmeyer, M.; Jablonka, P.; Hill, V.; Shetrone, M.; Tolstoy, E.; Irwin, M. J.; Battaglia, G.; Helmi, A.; Starkenburg, E.; Venn, K. A.; Abel, T.; Francois, P.; Kaufer, A.; North, P.; Primas, F.; Szeifert, T.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 524, id.A58, 21 pp.
Fecha de publicación:
12
2010
Revista
Número de citas
145
Número de citas referidas
122
Descripción
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
± 0.06 is the most metal-poor star ever observed in an external
galaxy. We carried out a detailed analysis of the chemical abundances of
the α, 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.
Tables 6 and 7 are only available in electronic form at http://www.aanda.org