Imaging Titan’s Organic Haze at Atomic Scale

Abstract Titan, Saturn’s largest moon, has its atmosphere filled with a thick organic photochemical haze. These suspended solid nanoparticles are one of the most complex materials in Solar System. In situ measurements from successful Cassini space mission gave first clues on aerosol's chemical composition: pyrolysis coupled to mass spectrometry revealed nitrogen-rich core, whereas infrared highlighted poly-aromatic-hydrocarbon (PAH) signatures. The combination these observations supports general model nitrogenated-polycyclic aromatic hydrocarbon (N-PAH). To constrain generic picture and understand formation such macromolecules Titan’s atmosphere, we simulated haze synthesis laboratory. Small (3–10 rings) N-PAH molecules composing material were extracted, focusing prime aromatization growth processes. By high-resolution atomic force microscopy (AFM), imaged key structures resolution. We resolved N-rich elongated involving five-membered rings, consistent repetitive cata -condensation pattern via addition C 3 N units. atomic-scale bridge gap between gas phase atmospheric reactants macroscopic structure