[C/Fe] as a function of log (L/L_⊙) for Galactic dwarf satellite and halo red giants. The Sculptor stars we analysed are represented by red squares and black asterisks. Burgundy squares denote the [C/Fe] abundances of Sculptor stars from the literature (Tafelmeyer et al. 2010; Frebel et al. 2010; Starkenburg et al. 2013b; Skúladóttir et al. 2015; Kirby et al. 2015; Simon et al. 2015). Small light blue asterisks are [C/Fe] measurements for dSph stars from literature data (Fulbright et al. 2004; Cohen & Huang 2009, 2010; Tafelmeyer et al. 2010; Norris et al. 2010; Lai et al. 2011; Honda et al. 2011; Venn et al. 2012). Empty green triangles represent the halo stars of Yong et al. (2013) with [Fe/H] ≥−3.0 dex. The dotted line is the Aoki et al. (2007) dividing line for carbon enhancement, which takes into account the depletion of carbon with evolution along the RGB.