Sprecher
Beschreibung
Barbara Ercolano
Polycyclic aromatic hydrocarbons (PAHs) are a pervasive component of astrophysical environments and represent a key reservoir of carbon in planetary systems. In this talk, I will present our efforts in understanding PAH formation, processing, and chemical impact in protoplanetary discs and planetary atmospheres, drawing on recent advances in coupled thermo-chemical and radiative transfer modelling.
I will show how stellar irradiation, atmospheric structure, and composition regulate PAH abundances, charge states, and size distributions across a wide range of environments. These properties, in turn, influence both the thermal balance and the broader chemical networks of atmospheres, with implications for observable signatures and atmospheric evolution.
Within this framework, I will discuss how aromatic species may contribute to the emergence of chemical complexity by acting as intermediates or catalytic platforms for the formation of more complex organic molecules. I will briefly highlight ongoing ab initio efforts that explore reaction pathways involving smaller nitrogen-bearing heteroaromatic ring systems (e.g. pyrimidine-like molecules) as computationally tractable proxies for more complex aromatic species. These calculations suggest that key prebiotic molecules, such as nucleobases, can form through exothermic gas-phase reactions with simple interstellar species, with quantum tunnelling likely playing an important role at low temperatures.
Taken together, these results point towards a scenario in which PAHs are not only tracers of carbon chemistry, but active participants in the chemical evolution of planetary environments. I will conclude by discussing how upcoming observations can test these ideas and constrain the role of aromatic chemistry in setting the stage for prebiotic processes beyond Earth.