Laboratory Investigation of CO2-Driven Enhancement of Radiolytic H2O2 on Europa and Other Icy Moons

Fuente: arXiv
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Main Authors: Mamo, Bereket D., Raut, Ujjwal, Teolis, Ben D., Erwin, Trevor P., Cartwright, Richard J., Protopapa, Silvia, Retherford, Kurt D., Nordheim, Tom A.
Format: Preprint
Published: 2025
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author Mamo, Bereket D.
Raut, Ujjwal
Teolis, Ben D.
Erwin, Trevor P.
Cartwright, Richard J.
Protopapa, Silvia
Retherford, Kurt D.
Nordheim, Tom A.
author_facet Mamo, Bereket D.
Raut, Ujjwal
Teolis, Ben D.
Erwin, Trevor P.
Cartwright, Richard J.
Protopapa, Silvia
Retherford, Kurt D.
Nordheim, Tom A.
contents Observations of Europa's leading hemisphere reveal elevated H2O2 in the warmer, low latitude chaos terrains compared to the colder, polar regions. This distribution disagrees with prior laboratory radiolysis studies of pure water ice, which show higher H2O2 yields at colder temperatures. The regions with higher peroxide abundance, Tara and Powys Regiones, also present increased amounts of CO2, possibly sourced from Europa's interior. To investigate whether CO2 influences radiolysis of water ice to boost H2O2 production, we irradiated water ice doped with varying amounts of CO2 with 10 keV electrons at 70 and 100 K. Our results indicate that CO2, even in trace amounts (< 3%), significantly enhances H2O2 yields at temperatures relevant to Europa. We discuss the mechanisms by which CO2 boosts peroxide synthesis and quantify H2O2 creation and destruction cross sections and G-values across different CO2 concentrations. These findings provide a plausible explanation for the perplexing H2O2 distribution on Europa and has implications for understanding peroxide on other icy bodies such as Ganymede and Charon, where it has been detected alongside CO2.
format Preprint
id arxiv_https___arxiv_org_abs_2506_15819
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Laboratory Investigation of CO2-Driven Enhancement of Radiolytic H2O2 on Europa and Other Icy Moons
Mamo, Bereket D.
Raut, Ujjwal
Teolis, Ben D.
Erwin, Trevor P.
Cartwright, Richard J.
Protopapa, Silvia
Retherford, Kurt D.
Nordheim, Tom A.
Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
Observations of Europa's leading hemisphere reveal elevated H2O2 in the warmer, low latitude chaos terrains compared to the colder, polar regions. This distribution disagrees with prior laboratory radiolysis studies of pure water ice, which show higher H2O2 yields at colder temperatures. The regions with higher peroxide abundance, Tara and Powys Regiones, also present increased amounts of CO2, possibly sourced from Europa's interior. To investigate whether CO2 influences radiolysis of water ice to boost H2O2 production, we irradiated water ice doped with varying amounts of CO2 with 10 keV electrons at 70 and 100 K. Our results indicate that CO2, even in trace amounts (< 3%), significantly enhances H2O2 yields at temperatures relevant to Europa. We discuss the mechanisms by which CO2 boosts peroxide synthesis and quantify H2O2 creation and destruction cross sections and G-values across different CO2 concentrations. These findings provide a plausible explanation for the perplexing H2O2 distribution on Europa and has implications for understanding peroxide on other icy bodies such as Ganymede and Charon, where it has been detected alongside CO2.
title Laboratory Investigation of CO2-Driven Enhancement of Radiolytic H2O2 on Europa and Other Icy Moons
topic Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2506.15819