{"id":{"repo_id":"mit","oai_identifier":"oai:dspace.mit.edu:1721.1/55066"},"canonical_url":"https://search.dev.ndltd.org/etd/mit/oai:dspace.mit.edu:1721.1/55066","repository":{"repo_id":"mit","name":"MIT","base_url":"https://dspace.mit.edu/oai/request"},"display":{"title":"The non-sphericity of Triton's atmosphere as evidenced by stellar occultations","abstract":"In an attempt to reconcile and understand recent measurements of the non-sphericity in Triton's atmosphere, the Tr148 occultation data set was reanalyzed. Recent new data from the Hubble Space Telescope Fine Guidance System allowed the separation and position angle of the Tr148 double star to be independently incorporated into the occultation analysis rather than being freely fit during the occultation reduction. The separation of 0.3855 ± 0.0004 arcsec and position angle of 67.17 ± 0.05 deg determined here differ from the values determined solely from the occultation timings of 0.3874 ± 0.0011 arcsec and 65.16 ± 0.14 deg. This resulted in a change in the calculated ellipticity and position angle of Triton's half-light ellipse from their originally fitted values of 0.029 ± 0.016 and 70.3 ± 10.1 deg to improved values of 0.033 ± 0.013 and 65.1 ± 8.8 deg. By fixing the separation parameters to independently determined values instead of freely fitting for them, the confidence in the new ellipticity fit (as measure by the reduced chi-squared results) is significantly increased. This work ends with a discussion of these new values and their implications for Triton's atmosphere.","abstract_html":"In an attempt to reconcile and understand recent measurements of the non-sphericity in Triton's atmosphere, the Tr148 occultation data set was reanalyzed. Recent new data from the Hubble Space Telescope Fine Guidance System allowed the separation and position angle of the Tr148 double star to be independently incorporated into the occultation analysis rather than being freely fit during the occultation reduction. The separation of 0.3855 ± 0.0004 arcsec and position angle of 67.17 ± 0.05 deg determined here differ from the values determined solely from the occultation timings of 0.3874 ± 0.0011 arcsec and 65.16 ± 0.14 deg. This resulted in a change in the calculated ellipticity and position angle of Triton's half-light ellipse from their originally fitted values of 0.029 ± 0.016 and 70.3 ± 10.1 deg to improved values of 0.033 ± 0.013 and 65.1 ± 8.8 deg. By fixing the separation parameters to independently determined values instead of freely fitting for them, the confidence in the new ellipticity fit (as measure by the reduced chi-squared results) is significantly increased. This work ends with a discussion of these new values and their implications for Triton's atmosphere.","abstract_has_math":false,"creators":["Person, Michael James"],"institution":"Massachusetts Institute of Technology","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences.","school":null,"contributors":[],"advisors":["James L. Elliot."],"committee_chairs":[],"committee_members":[],"year":2001,"date_issued":"2001","date_published":"2001","updated_at":"2026-07-22T22:22:29Z","subjects":["Earth, Atmospheric, and Planetary Sciences."],"languages":["eng"],"rights":["M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission."],"rights_urls":["http://dspace.mit.edu/handle/1721.1/7582"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1721.1/55066","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["James L. Elliot."]},{"key":"dc:contributor.department","label":"Department","values":["Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences."]},{"key":"dc:contributor.other","label":"Dc Contributor Other","values":["Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences."]},{"key":"dc:creator","label":"Author","values":["Person, Michael James"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2010-05-25T20:37:34Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2010-05-25T20:37:34Z"]},{"key":"dc:date.issued","label":"Date","values":["2001"]},{"key":"dc:publisher","label":"Institution","values":["Massachusetts Institute of Technology"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Earth, Atmospheric, and Planetary Sciences."]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission."]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://dspace.mit.edu/handle/1721.1/7582"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/1721.1/55066"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2001.","Includes bibliographical references (leaves 34-36)."]},{"key":"dc:description.abstract","label":"Abstract","values":["In an attempt to reconcile and understand recent measurements of the non-sphericity in Triton's atmosphere, the Tr148 occultation data set was reanalyzed. Recent new data from the Hubble Space Telescope Fine Guidance System allowed the separation and position angle of the Tr148 double star to be independently incorporated into the occultation analysis rather than being freely fit during the occultation reduction. The separation of 0.3855 ± 0.0004 arcsec and position angle of 67.17 ± 0.05 deg determined here differ from the values determined solely from the occultation timings of 0.3874 ± 0.0011 arcsec and 65.16 ± 0.14 deg. This resulted in a change in the calculated ellipticity and position angle of Triton's half-light ellipse from their originally fitted values of 0.029 ± 0.016 and 70.3 ± 10.1 deg to improved values of 0.033 ± 0.013 and 65.1 ± 8.8 deg. By fixing the separation parameters to independently determined values instead of freely fitting for them, the confidence in the new ellipticity fit (as measure by the reduced chi-squared results) is significantly increased. This work ends with a discussion of these new values and their implications for Triton's atmosphere."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["S.M."]},{"key":"dc:title","label":"Title","values":["The non-sphericity of Triton's atmosphere as evidenced by stellar occultations"]}]}],"canonical_facts":{"dc:contributor.advisor":["James L. Elliot."],"dc:contributor.department":["Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences."],"dc:contributor.other":["Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences."],"dc:creator":["Person, Michael James"],"dc:date.accessioned":["2010-05-25T20:37:34Z"],"dc:date.available":["2010-05-25T20:37:34Z"],"dc:date.issued":["2001"],"dc:description":["Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2001.","Includes bibliographical references (leaves 34-36)."],"dc:description.abstract":["In an attempt to reconcile and understand recent measurements of the non-sphericity in Triton's atmosphere, the Tr148 occultation data set was reanalyzed. Recent new data from the Hubble Space Telescope Fine Guidance System allowed the separation and position angle of the Tr148 double star to be independently incorporated into the occultation analysis rather than being freely fit during the occultation reduction. The separation of 0.3855 ± 0.0004 arcsec and position angle of 67.17 ± 0.05 deg determined here differ from the values determined solely from the occultation timings of 0.3874 ± 0.0011 arcsec and 65.16 ± 0.14 deg. This resulted in a change in the calculated ellipticity and position angle of Triton's half-light ellipse from their originally fitted values of 0.029 ± 0.016 and 70.3 ± 10.1 deg to improved values of 0.033 ± 0.013 and 65.1 ± 8.8 deg. By fixing the separation parameters to independently determined values instead of freely fitting for them, the confidence in the new ellipticity fit (as measure by the reduced chi-squared results) is significantly increased. This work ends with a discussion of these new values and their implications for Triton's atmosphere."],"dc:description.degree":["S.M."],"dc:identifier.uri":["http://hdl.handle.net/1721.1/55066"],"dc:language.iso":["eng"],"dc:publisher":["Massachusetts Institute of Technology"],"dc:rights":["M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission."],"dc:rights.uri":["http://dspace.mit.edu/handle/1721.1/7582"],"dc:subject":["Earth, Atmospheric, and Planetary Sciences."],"dc:title":["The non-sphericity of Triton's atmosphere as evidenced by stellar occultations"],"dc:type":["Thesis"]},"updated_at":"2026-07-22T22:22:29Z"}