Analysis of Two Carbon Stars in the Carina Dwarf Spheroidal Galaxy

We present a chemical analysis of two metal‐poor carbon stars belonging to the Carina Dwarf Spheroidal galaxy using high resolution optical spectra obtained with the VLT/UVES instrument. Their derived properties and chemical composition are compatible with these stars being in the TP‐AGB phase undergoing third dredge‐up episodes, although their extrinsic nature cannot be definitively discarded. The analysis indicates that these stars have large s‐element enhancements, which are compatible with theoretical s‐process nucleosynthesis predictions in low‐mass AGB stars $(∼1.5M⊙),$ and also large carbon enhancements $(C/O⩾5),$ much larger than the values typically found in galactic AGB carbon stars $(C/O∼1–2).$ This is also in agreement with the theoretical prediction that carbon stars are formed more easily through third dredge‐up episodes as the initial stellar metallicity drops. We speculate on the possibility that the abundance pattern found in the low‐mass s‐elements (Y, Zr) may be revealing the existence of some chemical depletion into dust grains.