Planetary scientists question the oceanic origin of organic molecules in the plumes of Enlade

The magnetosphere of Saturn contains trapped plasma and energetic loaded particles which constantly irritate the surface of Enlade. Plasma consists of a variety of loaded particles, including water group ions, formed mainly from high energy electrons interacting with the material of the plume. The observations of the instruments aboard the Cassini spacecraft of NASA show that on the interior icy satellites of Saturn, such as Mimas and Tethys, the irradiation by cold plasma darkens the spectra of reflectance and produces characteristics in the shape of Bullseye on the surfaces of the moons. However, in Enladus, the effects of bombing of plasma are unknown and difficult to determine.

“While the identification of complex organic molecules in the Enlaze environment remains an important index in the evaluation of the habitability of the Moon, the results demonstrate that chemistry focused on surface radiation and in plumes could also create these molecules,” said Dr. Grace Richards, researcher of the Nazional Istituto Di Astrofisica e Planetologa spaziale.

The plumes of Enceladus were discovered in 2005 by the Cassini spacecraft of NASA.

They emanate from long fractures called “tiger scratches” which are located in the southern polar region of Enceladus.

The water comes from an ocean sub-surface, and the energy to heat the ocean and producing the plumes is the result of gravitational tide forces from the massive interior of Saturn of Enladus.

Cassini stolen through the plumes, “tasting” some of the molecules in them and finding them rich in salts and containing a variety of organic compounds.

Like organic compounds, dissolved in an underground ocean of water, could transform into prebiotic molecules which are the precursors of life, these results interested a great interest in astrobiologists.

However, the new results show that exposure to the radiation trapped in the powerful magnetosphere of Saturn could trigger the formation of these organic compounds on the ice surface of Enlade. This questions their astrobiological relevance.

In their research, Dr. Richards and his colleagues simulated the composition of ice on the surface and within the walls of the Tigers of Enladus.

This ice contained water, carbon dioxide, methane and ammonia and was cooled at less than 200 degrees Celsius.

The researchers then bombed the ice with ions to reproduce the radiation environment around Encelade.

The ions reacted with the frozen components, creating a whole band of molecular species, including carbon monoxide, cyanate and ammonium.

They have also produced molecular precursors in amino acids, of which chains form proteins which cause metabolic reactions, repair cells and transmit nutrients in life forms.

Some of these compounds have already been detected on the surface of Enlade, but others have also been identified in the plumes.

“The molecules considered to be prebiotic could form plausibly in situ by the treatment of radiation, rather than necessarily of origin of the underground ocean,” said Dr. Richards.

“Although this does not exclude the possibility that the ocean of Enlade is habitable, it means that we must be careful to make this hypothesis simply because of the composition of the plumes.”

“Understand how to differentiate between organic matter derived from the ocean and the molecules formed by radiation interacting with the surface and the stripes of the tiger will be very difficult.”

“More data from future missions will be necessary, such as a proposed prapping mission which is currently being studied within the framework of the 2050 travel recommendations for the ESA scientific program until the middle of the century.”

The team’s conclusions were presented earlier this month EPSC-DPS2025 joint meeting In Helsinki, Finland.

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Grace Richards and al. 2025. Studies to irradiation of the ions of the water group of analogues of Enlaze surface. EPSC abstracts 18: EPSC-DPS2025-264; DOI: 10.5194 / EPSC-DPS2025-264