Show simple item record

dc.contributor.advisorHubbard, William B.
dc.contributor.authorMarcialis, Robert Louis.
dc.creatorMarcialis, Robert Louis.en_US
dc.date.accessioned2011-10-31T17:24:47Z
dc.date.available2011-10-31T17:24:47Z
dc.date.issued1990en_US
dc.identifier.urihttp://hdl.handle.net/10150/185001
dc.description.abstractThis year is the last of a five-year interval when the Earth passes through the orbital plane of Pluto and its satellite Charon, causing alternate transits and occultations of the satellite as seen from Earth. Spectrophotometric observations of the system made both in and out of eclipse have been obtained in the visual and near-infrared. The Pluto-Charon system is found to be compositionally diverse, a result unanticipated before the mutual events. Water frost has been identified and is ubiquitous on Charon's surface, while Pluto has a methane veneer. The spectral activity of Pluto's methane is seen to vary with rotational phase, i.e., planetary longitude. On Pluto, surface albedo appears to be correlated with composition. Dark regions tend to be redder and depleted in methane relative to bright regions. Dependence of geometric albedo with wavelength has been calculated for both bodies, from 0.4 to 2.4 μm. The albedo model of Marcialis (1983, 1988) has emerged favorably after several severe tests. Accurate radii and system bulk density derived from the mutual events have been used to construct models of phenomena unanticipated a decade ago. Charon's gravity is feeble enough that it could have shed a substantial primordial methane inventory to space and to Pluto, thereby explaining its different surface composition and lower albedo. Recent interior models are used to show that viscous relaxation of topography is expected to be significant on Pluto but not on Charon. Horizontal topographic features on the primary probably are limited in extent to less than a few tens of kilometers (or are geologically young), much as has been found subsequently for Triton. Globally, Pluto's figure is essentially hydrostatic. Astrometric observations of the system are presented, as is evidence that the discovery of Charon just seven years before the initial mutual events was not fortuitous, but most probable. The astrometry will help to refine Pluto's orbit, making prediction of future stellar occultations by the system more reliable.
dc.language.isoenen_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.subjectPhysicsen_US
dc.titleThe Pluto-Charon system as revealed during the mutual events.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.identifier.oclc708084233en_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.identifier.proquest9024512en_US
thesis.degree.disciplinePlanetary Sciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.namePh.D.en_US
refterms.dateFOA2018-08-13T19:36:13Z
html.description.abstractThis year is the last of a five-year interval when the Earth passes through the orbital plane of Pluto and its satellite Charon, causing alternate transits and occultations of the satellite as seen from Earth. Spectrophotometric observations of the system made both in and out of eclipse have been obtained in the visual and near-infrared. The Pluto-Charon system is found to be compositionally diverse, a result unanticipated before the mutual events. Water frost has been identified and is ubiquitous on Charon's surface, while Pluto has a methane veneer. The spectral activity of Pluto's methane is seen to vary with rotational phase, i.e., planetary longitude. On Pluto, surface albedo appears to be correlated with composition. Dark regions tend to be redder and depleted in methane relative to bright regions. Dependence of geometric albedo with wavelength has been calculated for both bodies, from 0.4 to 2.4 μm. The albedo model of Marcialis (1983, 1988) has emerged favorably after several severe tests. Accurate radii and system bulk density derived from the mutual events have been used to construct models of phenomena unanticipated a decade ago. Charon's gravity is feeble enough that it could have shed a substantial primordial methane inventory to space and to Pluto, thereby explaining its different surface composition and lower albedo. Recent interior models are used to show that viscous relaxation of topography is expected to be significant on Pluto but not on Charon. Horizontal topographic features on the primary probably are limited in extent to less than a few tens of kilometers (or are geologically young), much as has been found subsequently for Triton. Globally, Pluto's figure is essentially hydrostatic. Astrometric observations of the system are presented, as is evidence that the discovery of Charon just seven years before the initial mutual events was not fortuitous, but most probable. The astrometry will help to refine Pluto's orbit, making prediction of future stellar occultations by the system more reliable.


Files in this item

Thumbnail
Name:
azu_td_9024512_sip1_m.pdf
Size:
3.205Mb
Format:
PDF
Description:
azu_td_9024512_sip1_m.pdf

This item appears in the following Collection(s)

Show simple item record