Researchers from the Institute of Astronomy of the Russian Academy of Sciences, including M. S. Murga, I. V. Loginov, D. S. Wiebe, D. R. Fedotova, V. S. Krasnoukhov, and I. O. Antonov, have published a study in the Astrophysical Journal that explores the role of dust grains in the formation of aromatic hydrocarbons in the envelopes of carbon-rich asymptotic giant branch (AGB) stars. This research, titled “The impact of surface acetylene cyclotrimerization on the abundance of aromatic hydrocarbons in carbon-rich asymptotic giant branch stars,” provides insights that could have implications for understanding the origins of complex organic molecules in space and potentially for the energy industry.
The study focuses on the process of acetylene cyclotrimerization, where three acetylene molecules combine to form benzene, a simple aromatic hydrocarbon. This reaction occurs on the surfaces of dust grains within the circumstellar envelopes of AGB stars. The researchers developed a comprehensive computational model that couples gas-phase, gas-surface, and surface reactions, as well as the physical evolution of dust grains. This model expands on previous chemical networks by including updated reactions involving hydrocarbons up to pyrene, a larger polycyclic aromatic hydrocarbon.
By simulating the chemical evolution of the envelope of the prototypical AGB star IRC+10216, the researchers compared scenarios with and without the cyclotrimerization reaction. They found that surface-catalyzed cyclotrimerization significantly enhances the abundance of aromatic species, potentially increasing their total abundance by up to an order of magnitude. The study highlights the interconnected nature of gas-phase chemistry and dust surface processes, emphasizing the need for self-consistent modeling to accurately predict chemical abundances.
For the energy industry, understanding the formation of aromatic hydrocarbons in space can provide insights into the origins of complex organic molecules that may be relevant to fossil fuel formation. Polycyclic aromatic hydrocarbons (PAHs), for instance, are known to be present in fossil fuels and are a byproduct of combustion processes. The research could contribute to a broader understanding of the chemical processes that lead to the formation of these compounds, potentially aiding in the development of more efficient and cleaner energy technologies.
The researchers also underscore the importance of constraining uncertain parameters, such as the desorption energies of hydrocarbons, for future realistic modeling of astrochemical processes. This work not only advances our knowledge of chemical evolution in evolved stellar systems but also offers valuable insights that could be applied to the energy sector. The study was published in the Astrophysical Journal, a leading journal in the field of astrophysics.
This article is based on research available at arXiv.