Detection of a population of carbon-enhanced metal-poor stars in the
  Sculptor dwarf spheroidal galaxy
  The study of the chemical abundances of metal-poor stars in dwarf galaxies
provides a venue to constrain paradigms of chemical enrichment and galaxy
formation. Here we present metallicity and carbon abundance measurements of 100
stars in Sculptor from medium-resolution (R ~ 2000) spectra taken with the
Magellan/Michigan Fiber System mounted on the Magellan-Clay 6.5m telescope at
Las Campanas Observatory. We identify 24 extremely metal-poor star candidates
([Fe/H] < -3.0) and 21 carbon-enhanced metal-poor (CEMP) star candidates. Eight
carbon-enhanced stars are classified with at least 2$\sigma$ confidence and
five are confirmed as such with follow-up R~6000 observations using the
Magellan Echellette Spectrograph on the Magellan-Baade 6.5m telescope. We
measure a CEMP fraction of 36% for stars below [Fe/H] = -3.0, indicating that
the prevalence of carbon-enhanced stars in Sculptor is similar to that of the
halo (~43%) after excluding likely CEMP-s and CEMP-r/s stars from our sample.
However, we do not detect that any CEMP stars are strongly enhanced in carbon
(e.g., [C/Fe] > 1.0). The existence of a large number of CEMP stars both in the
halo and in Sculptor suggests that some halo CEMP stars may have originated
from accreted early analogs of dwarf galaxies.
