Polycyclic aromatic hydrocarbons in carbonaceous chondrites can be used as tracers of both pre-accretion and secondary processes

Carbonaceous chondrites contain a diverse suite of more or less soluble compounds, including polycyclic aromatic hydrocarbons (PAHs). These compounds are structured around two fused benzene rings, and have shown to be detected in various astrophysical environments. The origin PAHs carbonaceous is debated: they may originate from the interstellar medium (ISM) thus potentially carry information on accretion processes. Alternatively, formed transformed during secondary processes parent bodies about aqueous alteration conditions. Here, we investigate nature, quantity, isotopic composition free three recently recovered CM having experienced substantial distinct degrees alteration: CM2.2 Aguas Zarcas, CM2.0 Mukundpura CM1/2 Kolang. All CMs investigated PAHs, with sizes ranging 2 (naphthalene) 5 cycles (benzopyrene). concentration not correlated degree larger also most depleted 13C, suggesting an origin. Yet, abundance alkylated appears all extracted D-depleted, pointing towards hydrogen exchange water occurred alteration. combined results suggest that CCs likely both