Photochemistry Of Interstellar Ice Forming Complex Organic Molecules
Processes expected to play a role in interstellar ice are simulated in the laboratory. Energetic photons and ions lead to fragmentation or desorption of molecules from the ice. The end result is the synthesis of complex organic molecules (COMs) that remain in the dust, and may occasionally desorb during irradiation, or later upon warm-up as the icy dust grains experience heating in e.g., warmer regions of protoplanetary disks.
Astrochemistry is a well-established multidisciplinary field devoted to study molecules in space. While most astrochemists are oriented to observe molecules in the gas phase and reproduce their abundances by modeling the physical conditions of the medium, the microscopic dust particles wandering in the interstellar medium deserve the attention of a smaller community.
Radiation and thermally-driven processes taking place in the bare dust, and particularly in dust particles covered by ice mantles, are mimicked in the laboratory. In addition to water, interstellar ice contains other simple species.
In this Review we present our current knowledge on ice photochemistry and thermal processing that ultimately leads to formation of complex organic molecules (COMs). Numerous COMs are of astrobiological interest and match those present in comets and asteroids.
Upon impact of these minor bodies, water and COMs were delivered to the earth and might have intervened in the first prebiotic reactions.
Guillermo M. Muñoz Caro, Héctor Carrascosa de Lucas, Rafael Martín-Doménech
Subjects: Astrophysics of Galaxies (astro-ph.GA); Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2512.08413 [astro-ph.GA](or arXiv:2512.08413v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2512.08413
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Journal reference: Nat. Rev. Chem., 9, 537-552 (2025)
Related DOI:
https://doi.org/10.1038/s41570-025-00729-z
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Submission history
From: Guillermo M. Muñoz Caro
[v1] Tue, 9 Dec 2025 09:42:18 UTC (5,652 KB)
https://arxiv.org/abs/2512.08413
Astrobiology, Astrochemistry,
