{"id":{"repo_id":"mit","oai_identifier":"oai:dspace.mit.edu:1721.1/90651"},"canonical_url":"https://search.dev.ndltd.org/etd/mit/oai:dspace.mit.edu:1721.1/90651","repository":{"repo_id":"mit","name":"MIT","base_url":"https://dspace.mit.edu/oai/request"},"display":{"title":"Effects of Earth encounters on the physical properties of near-earth objects","abstract":"The effects of Earth encounters on the physical properties of near-Earth objects (NEOs) have been shown to be significant factors in their evolution. Previous studies have examined the effects of these encounters on reflectance spectra based on observational measurements, and effects such as spin state and shape changes have been studied for specific asteroids and through simulation. In this project, an automated light-curve fitting routine was developed to support data reduction in an ongoing NEO survey. Additionally, data from previous NEO surveys were used to support simulation results by showing differences between encounter and non-encounter populations' rotational frequency distributions. These results demonstrate that Earth encounters have an effect on asteroid rotation by increasing the overall frequency as well as causing a wider distribution of frequencies when compared to non-encounter populations of NEOs. These data were, however, unable to show any effect on asteroid shape brought on by planetary encounters. A frequency comparison between NEOs that likely had Earth encounters to main-belt-equivalent asteroids did not show the same encounter effect, though the 'equivalent' asteroid populations were likely affected by a size/spin-rate bias.","abstract_html":"The effects of Earth encounters on the physical properties of near-Earth objects (NEOs) have been shown to be significant factors in their evolution. Previous studies have examined the effects of these encounters on reflectance spectra based on observational measurements, and effects such as spin state and shape changes have been studied for specific asteroids and through simulation. In this project, an automated light-curve fitting routine was developed to support data reduction in an ongoing NEO survey. Additionally, data from previous NEO surveys were used to support simulation results by showing differences between encounter and non-encounter populations' rotational frequency distributions. These results demonstrate that Earth encounters have an effect on asteroid rotation by increasing the overall frequency as well as causing a wider distribution of frequencies when compared to non-encounter populations of NEOs. These data were, however, unable to show any effect on asteroid shape brought on by planetary encounters. A frequency comparison between NEOs that likely had Earth encounters to main-belt-equivalent asteroids did not show the same encounter effect, though the 'equivalent' asteroid populations were likely affected by a size/spin-rate bias.","abstract_has_math":false,"creators":["Siu, Ho Chit"],"institution":"Massachusetts Institute of Technology","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Massachusetts Institute of Technology. Department of Aeronautics and Astronautics.","school":null,"contributors":[],"advisors":["Richard P. Binzel and Nicholas A. Moskovitz."],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014","date_published":"2014","updated_at":"2026-07-22T22:21:03Z","subjects":["Aeronautics and Astronautics."],"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/1721.1/90651","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Richard P. Binzel and Nicholas A. Moskovitz."]},{"key":"dc:contributor.department","label":"Department","values":["Massachusetts Institute of Technology. Department of Aeronautics and Astronautics."]},{"key":"dc:contributor.other","label":"Dc Contributor Other","values":["Massachusetts Institute of Technology. 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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/1721.1/90651"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Thesis: S.B., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2014.","Cataloged from PDF version of thesis.","Includes bibliographical references (pages 56-57)."]},{"key":"dc:description.abstract","label":"Abstract","values":["The effects of Earth encounters on the physical properties of near-Earth objects (NEOs) have been shown to be significant factors in their evolution. Previous studies have examined the effects of these encounters on reflectance spectra based on observational measurements, and effects such as spin state and shape changes have been studied for specific asteroids and through simulation. In this project, an automated light-curve fitting routine was developed to support data reduction in an ongoing NEO survey. Additionally, data from previous NEO surveys were used to support simulation results by showing differences between encounter and non-encounter populations' rotational frequency distributions. These results demonstrate that Earth encounters have an effect on asteroid rotation by increasing the overall frequency as well as causing a wider distribution of frequencies when compared to non-encounter populations of NEOs. These data were, however, unable to show any effect on asteroid shape brought on by planetary encounters. A frequency comparison between NEOs that likely had Earth encounters to main-belt-equivalent asteroids did not show the same encounter effect, though the 'equivalent' asteroid populations were likely affected by a size/spin-rate bias."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["S.B."]},{"key":"dc:title","label":"Title","values":["Effects of Earth encounters on the physical properties of near-earth objects"]}]}],"canonical_facts":{"dc:contributor.advisor":["Richard P. Binzel and Nicholas A. Moskovitz."],"dc:contributor.department":["Massachusetts Institute of Technology. Department of Aeronautics and Astronautics."],"dc:contributor.other":["Massachusetts Institute of Technology. Department of Aeronautics and Astronautics."],"dc:creator":["Siu, Ho Chit"],"dc:date.accessioned":["2014-10-08T15:20:33Z"],"dc:date.available":["2014-10-08T15:20:33Z"],"dc:date.issued":["2014"],"dc:description":["Thesis: S.B., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2014.","Cataloged from PDF version of thesis.","Includes bibliographical references (pages 56-57)."],"dc:description.abstract":["The effects of Earth encounters on the physical properties of near-Earth objects (NEOs) have been shown to be significant factors in their evolution. Previous studies have examined the effects of these encounters on reflectance spectra based on observational measurements, and effects such as spin state and shape changes have been studied for specific asteroids and through simulation. In this project, an automated light-curve fitting routine was developed to support data reduction in an ongoing NEO survey. Additionally, data from previous NEO surveys were used to support simulation results by showing differences between encounter and non-encounter populations' rotational frequency distributions. These results demonstrate that Earth encounters have an effect on asteroid rotation by increasing the overall frequency as well as causing a wider distribution of frequencies when compared to non-encounter populations of NEOs. These data were, however, unable to show any effect on asteroid shape brought on by planetary encounters. A frequency comparison between NEOs that likely had Earth encounters to main-belt-equivalent asteroids did not show the same encounter effect, though the 'equivalent' asteroid populations were likely affected by a size/spin-rate bias."],"dc:description.degree":["S.B."],"dc:identifier.uri":["http://hdl.handle.net/1721.1/90651"],"dc:language.iso":["eng"],"dc:publisher":["Massachusetts Institute of Technology"],"dc:rights":["M.I.T. theses are protected by copyright. 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