Publication Date:
2010-11-27
Description:
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.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Teolis, B D -- Jones, G H -- Miles, P F -- Tokar, R L -- Magee, B A -- Waite, J H -- Roussos, E -- Young, D T -- Crary, F J -- Coates, A J -- Johnson, R E -- Tseng, W-L -- Baragiola, R A -- New York, N.Y. -- Science. 2010 Dec 24;330(6012):1813-5. doi: 10.1126/science.1198366. Epub 2010 Nov 25.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Southwest Research Institute, Space Science and Engineering Division, 6220 Culebra Road, San Antonio, TX 78238, USA. ben.teolis@swri.org〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21109635" target="_blank"〉PubMed〈/a〉
Keywords:
Atmosphere
;
*Carbon Dioxide
;
Extraterrestrial Environment
;
Ice
;
Mass Spectrometry
;
*Oxygen
;
Photochemical Processes
;
*Saturn
;
Spacecraft
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
