The Formation of Benzene in Dense Environments

PAHs are traditionally thought to form around carbon-rich AGB stars, where the presence of inner-wind shocks and nucleation seeds can aid their formation. However, my recent work has shown that the formation of benzene – thought to be the rate-limiting step in the formation of larger PAHs – can be efficient in other environments, namely the dense tori around the evolved stars of pre-planetary nebulae and in the inner regions of the accretion discs around young stars. I will discuss the chemical pathways to the formation of benzene in these regions and the subsequent formation of larger PAHs.