2010/11/26 by B. D. Teolis, G. H. Jones, P. F. Miles +10 · 2 citations
Physics and Astronomy · Chemistry · #Astro and Planetary Science #Planetary Science and Exploration #Astrophysics and Star Formation Studies #Astrobiology #Icy moon #Atmosphere (unit) #Outgassing #Saturn #Carbon dioxide #Oxygen #Radiolysis #Planet #Chemistry #Physics #Astronomy #Irradiation #Meteorology
paper · doi:10.1126/science.1198366
openalex publication_date 2010/11/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
The flyby measurements of the Cassini spacecraft at Saturn's moon Rhea reveal a tenuous oxygen (O(2))-carbon dioxide (CO(2)) atmosphere. The atmosphere appears to be sustained by chemical decomposition of the surface water ice under irradiation from Saturn's magnetospheric plasma. This in situ detection of an oxidizing atmosphere is consistent with remote observations of other icy bodies, such as Jupiter's moons Europa and Ganymede, and suggestive of a reservoir of radiolytic O(2) locked within Rhea's ice. The presence of CO(2) suggests radiolysis reactions between surface oxidants and organics or sputtering and/or outgassing of CO(2) endogenic to Rhea's ice. Observations of outflowing positive and negative ions give evidence for pickup ionization as a major atmospheric loss mechanism.