Formation of atmospheres from icy surfaces

We study the formation of atmospheres from icy surfaces due to electron precipitation, relevant for the icy moons of the solar system. Using a setup similar as described in reference [1], we conduct laboratory experiments irradiating macroscopic ice samples [2] with electrons, to simulate the processing of the icy moons’ surfaces. The experiments are conducted in high vacuum and at a temperature of 95 K to 105 K, reflecting the conditions at the icy moons. Using a time-of-flight mass spectrometer, we measure the sputter yields of water and radiolytic products, such as the species H, H2, O, OH, H2O, O2, H2O2, and O3. We also measure the timescales of release of the species, and particularly the oxygen retention in ice.

The ice sputter yields of less produced species are critical to model the atmosphere of the icy moons [3] and necessary to infer the surface composition of the icy moons using data from the upcoming Jupiter Icy Moons Explorer and Europa Clipper missions.

[1] Tinner, Chantal, et al. "Electron‐induced radiolysis of water ice and the buildup of oxygen." Journal of Geophysical Research: Planets 129.12 (2024): e2024JE008393.

[2] Pommerol, Antoine, et al. "Experimenting with mixtures of water ice and dust as analogues for icy planetary material: recipes from the ice laboratory at the University of Bern." Space science reviews 215 (2019): 1-68.

[3] Vorburger, Audrey, and Peter Wurz. "Europa’s ice-related atmosphere: the sputter contribution." Icarus 311 (2018): 135-145.