Processing of methane and acetylene ices by galactic cosmic rays and implications to the color diversity of Kuiper Belt objects.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37256949.
- Also identified by DOI 10.1126/sciadv.adg6936 and PMC identifier 10413643.
- Licence recorded as CC BY-NC.
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Abstract
Kuiper Belt objects exhibit a wider color range than any other solar system population. The origin of this color diversity is unknown, but likely the result of the prolonged irradiation of organic materials by galactic cosmic rays (GCRs). Here, we combine ultrahigh-vacuum irradiation experiments with comprehensive spectroscopic analyses to examine the color evolution during GCR processing methane and acetylene under Kuiper Belt conditions. This study replicates the colors of a population of Kuiper Belt objects such as Makemake, Orcus, and Salacia. Aromatic structural units carrying up to three rings as in phenanthrene (C<sub>14</sub>H<sub>10</sub>), phenalene (C<sub>9</sub>H<sub>10</sub>), and acenaphthylene (C<sub>12</sub>H<sub>8</sub>), of which some carry structural motives of DNA and RNA connected via unsaturated linkers, were found to play a key role in producing the reddish colors. These studies demonstrate the level of molecular complexity synthesized of GCR processing hydrocarbon and hint at the role played by irradiated ice in the early production of biological precursor molecules.