The JWST Proto-PAH project: Aromatic backbones with extensive aliphatic substitution account for both the aromatic and aliphatic emission

We find that the aromatic and aliphatic emission bands in four carbon-rich post-asymptotic giant branch stars with class D emission arise from a single carrier population: extensive aliphatic decoration of an aromatic skeleton, i.e. molecules with a coherent aromatic backbone and an unusually high a