Published online by Cambridge University Press: 26 May 2016
The chemical abundances of Wolf-Rayet ([WC]) central stars are reviewed. Although the evolutionary connection between cooler (late) and hotter (early) [WC] central stars and PG1159 central stars is now on solid ground, several issues still remain. In particular, hydrogen and oxygen abundances, that could provide a way of discriminating between different evolutionary channels, are affected by large uncertainties. Following the ground-breaking discovery that cool [WC] central stars harbor hot carbon- as well as hot oxygen-rich dust, current theories of their origin have been put in serious doubt. Observations of three cool [WC] central stars are presented here which, while confirming the deficiency of our theoretical understanding, hint at the possibility of alternative scenarios, such as dust-storing disks.