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Caloris Basin - An enhanced source for potassium in Mercury's atmosphereEnhanced abundances of neutral K in the atmosphere of Mercury have been found above the longitude range containing Caloris Basin. Results of a large data set including six elongations of the planet between June 1986 and January 1988 show typical K column abundances of about 5.4 x 10 to the 8th K atmos/sq cm. During the observing period in October 1987, when Caloris Basin was in view, the typical K column was about 2.7 x 10 to the 9th K atoms/sq cm. Another large value was seen over the Caloris antipode in January 1988. This enhancement is consistent with an increased source of K from the well-fractured crust and regolith associated with this large impact basin. The phenomenon is localized because at most solar angles, thermal alkali atoms cannot move more than a few hundred kilometers from their source before being lost to ionization by solar ultraviolet radiation.
Document ID
19900062890
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Sprague, Ann L.
(NASA Ames Research Center Moffett Field, CA, United States)
Kozlowski, Richard W. H.
(NASA Ames Research Center Moffett Field, CA, United States)
Hunten, Donald M.
(Arizona, University Tucson, United States)
Date Acquired
August 14, 2013
Publication Date
September 7, 1990
Publication Information
Publication: Science
Volume: 249
ISSN: 0036-8075
Subject Category
Lunar And Planetary Exploration
Accession Number
90A49945
Funding Number(s)
CONTRACT_GRANT: NAG2-143
CONTRACT_GRANT: NGT-5005065
Distribution Limits
Public
Copyright
Other

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