Persistent Link:
http://hdl.handle.net/10150/185067
Title:
An observational comparison of mercury and the moon.
Author:
Sprague, Ann Louise.
Issue Date:
1990
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Observations of the neutral sodium (Na) and neutral potassium (K) atoms in the tenuous atmospheres of the Moon and Mercury have been made, analyzed and interpreted. An atmospheric number density of ∼300 times more Na and ∼100 times more K are observed at Mercury than at the Moon. This is not consistent with a meteoritic source for these constituents unless losses and recycling are very different. Potassium observations in the lunar atmosphere indicate fewer accommodated atoms than expected from thermalization of the extended component through gas-surface interactions. A mechanism for redistributing the thermal and non-thermal populations is presented. Thermal infrared observations between 7.5 and 12.5 μm have been made at both bodies in an attempt to gain understanding of the relationship of the surfaces to the alkali atmospheres. Mercury has been found to have a surface composition at three locations more felsic than that of the lunar south-polar highlands. Spectral indications of high alkali feldspar have been observed. One mafic location on Mercury's surface has been determined. Calculations using a grain-boundary and regolith diffusion model have shown that the differences in abundances of Na and K and the ratios of Na/K at both bodies can be explained by a supply of atoms diffusing upward through the sub-surface materials over geologic time. Enhancements in K seen at the longitude of Caloris and the antipodal point of up to five (5) and four (4) respectively, point to a sub-surface source for at least part of the tenuous alkali atmosphere at Mercury.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Physics
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Planetary Science; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Hunten, Donald

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleAn observational comparison of mercury and the moon.en_US
dc.creatorSprague, Ann Louise.en_US
dc.contributor.authorSprague, Ann Louise.en_US
dc.date.issued1990en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractObservations of the neutral sodium (Na) and neutral potassium (K) atoms in the tenuous atmospheres of the Moon and Mercury have been made, analyzed and interpreted. An atmospheric number density of ∼300 times more Na and ∼100 times more K are observed at Mercury than at the Moon. This is not consistent with a meteoritic source for these constituents unless losses and recycling are very different. Potassium observations in the lunar atmosphere indicate fewer accommodated atoms than expected from thermalization of the extended component through gas-surface interactions. A mechanism for redistributing the thermal and non-thermal populations is presented. Thermal infrared observations between 7.5 and 12.5 μm have been made at both bodies in an attempt to gain understanding of the relationship of the surfaces to the alkali atmospheres. Mercury has been found to have a surface composition at three locations more felsic than that of the lunar south-polar highlands. Spectral indications of high alkali feldspar have been observed. One mafic location on Mercury's surface has been determined. Calculations using a grain-boundary and regolith diffusion model have shown that the differences in abundances of Na and K and the ratios of Na/K at both bodies can be explained by a supply of atoms diffusing upward through the sub-surface materials over geologic time. Enhancements in K seen at the longitude of Caloris and the antipodal point of up to five (5) and four (4) respectively, point to a sub-surface source for at least part of the tenuous alkali atmosphere at Mercury.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectPhysicsen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplinePlanetary Scienceen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorHunten, Donalden_US
dc.identifier.proquest9025086en_US
dc.identifier.oclc708252725en_US
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