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Io's atmosphere from microwave detection SO2The microwave detection of SO2 at 222 GHz in Io's atmosphere is reported. The observations imply an SO2 surface pressure of 4-35 nanobars, covering 3-15 percent of the surface on both leading and trailing sides of Io when illuminated by the sun. This supports atmospheric models in which the partial pressure of SO2 at the surface is determined by the Io surface temperature, favoring, in particular, the 'albedo cold-trap' models. The failure to detect H2S at 169 GHz suggests that the pressure of this gas is probably below 10 to the -10th bar. These results, taken together with Pioneer ionospheric data, suggest that an atmospheric gas other than SO2 is present. It is proposed that the locally buffered SO2 atmosphere coexists with a background atmosphere of oxygen with a partial surface pressure of about 20 nanobars.
Document ID
19900060019
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Lellouch, Emmanuel
(Observatoire de Paris-Meudon France)
Encrenaz, Therese
(Paris Observatoire, Meudon, France)
Belton, Michael
(National Optical Astronomy Observatories Tucson, AZ, United States)
De Pater, Imke
(California, University Berkeley, United States)
Gulkis, Samuel
(JPL Pasadena, CA, United States)
Date Acquired
August 14, 2013
Publication Date
August 16, 1990
Publication Information
Publication: Nature
Volume: 346
ISSN: 0028-0836
Subject Category
Lunar And Planetary Exploration
Accession Number
90A47074
Distribution Limits
Public
Copyright
Other

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