2018ApJ...856..142C -
Astrophys. J., 856, 142-142 (2018/April-1)
Detection of a population of carbon-enhanced metal-poor stars in the Sculptor dwarf spheroidal galaxy.
CHITI A., SIMON J.D., FREBEL A., THOMPSON I.B., SHECTMAN S.A., MATEO M., BAILEY J.I., CRANE J.D. and WALKER M.
Abstract (from CDS):
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 6.5 m 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 2σ confidence, and five are confirmed as such with follow-up R ∼ 6000 observations using the Magellan Echellette Spectrograph on the Magellan-Baade 6.5 m 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 ([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.
Abstract Copyright:
© 2018. The American Astronomical Society. All rights reserved.
Journal keyword(s):
galaxies: dwarf - galaxies: individual: Sculptor dSph - galaxies: stellar content - stars: abundances - stars: carbon
VizieR on-line data:
<Available at CDS (J/ApJ/856/142): table5.dat table6.dat>
Nomenclature:
Tables 5-6: [CSF2018] FF-N-NNNN N=26+100.
Simbad objects:
119
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