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Updated: Jul 7, 2025

On-line Analysis of Nitrogen Containing Compounds in Complex Hydrocarbon Matrixes
Published on: August 5, 2016
Polycyclic aromatic hydrocarbons in samples of Ryugu formed in the interstellar medium
Sarah S Zeichner1, José C Aponte2, Surjyendu Bhattacharjee1
1Geological and Planetary Science Division, California Institute of Technology, Pasadena, CA 91125, USA.
Abstract:
Polycyclic aromatic hydrocarbons (PAHs) contain ≲20% of the carbon in the interstellar medium. They are potentially produced in circumstellar environments (at temperatures ≳1000 kelvin), by reactions within cold (~10 kelvin) interstellar clouds, or by processing of carbon-rich dust grains. We report isotopic properties of PAHs extracted from samples of the asteroid Ryugu and the meteorite Murchison. The doubly-13C substituted compositions (Δ2×13C values) of the PAHs naphthalene, fluoranthene, and pyrene are 9 to 51‰ higher than values expected for a stochastic distribution of isotopes. The Δ2×13C values are higher than expected if the PAHs formed in a circumstellar environment, but consistent with formation in the interstellar medium. By contrast, the PAHs phenanthrene and anthracene in Ryugu samples have Δ2×13C values consistent with formation by higher-temperature reactions.
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