Dinâmica de uma partícula coorbital a um sistema de satélites
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Data
2003
Autores
Silva, Priscila Alves da [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Pequenos satélites podem ser os responsáveis pela variedade de estruturas encontradas nos anéis planetários estreitos. Os anéis da Falha de Encke e o anel F de Saturno apresentam estranhas características, denominadas de aglomerados e kinks, que podem estar relacionadas com esses pequenos satélites. Com o intuito de analisar o comportamento de partículas pertencentes a um anel sob o efeito desses satélites foram numericamente simulados vários sistemas possuindo dois e três satélites. Nessas simulações os satélites, com mesma razão de massa, foram inicialmente localizados em posições de equilíbrio determinadas por Salo & Yoder (1988). Os resultados mostraram que, dependendo da excentricidade das partículas e dos satélites, o anel pode apresentar variações azimutal e radial ao longo de toda a sua extensão. Embora essas variações possam explicar os aglomerados encontrados nos anéis, as simulações numéricas também evidenciaram a característica temporária dessas estruturas, principalmente quando o achatamento do corpo principal (planeta) foi incluído. Para o caso dos anéis da Falha de Encke a inclusão desses pequenos satélites, como proposto por Ferrari & Brahic (1997), pode causar a destruição dos anéis em aproximadamente 200 anos. Foi verificado que o sistema anel F-Prometeu-Pandora é extremamente sensível às condições iniciais, algumas partículas podem permanecer em órbitas de ferradura por um curto período de tempo para determinadas condições iniciais. Esse resultado está de acordo com os trabalhos recentes que mostram que os dois satélites Prometeu e Pandora têm um movimento caótico. Complementares a esse estudo foram obtidos os pontos de equilíbrio para as partículas e para os satélites (com massas diferentes). Essa análise foi baseada no problema circular restrito de três corpos...
Hypothetical moonlets are claimed to be reponsible for a variety of structures found in narrow planetary rings. The Encke gap ringlets and theF ring of Saturn present strange features, such as clumps and kinks, wich can be related to the presence of these hypothetical moonlets. In an attempt to understand the behavior og the ring particles under the effects of these embedded moonlets, numerical simulations have been carried out for a system composed of two and three moonlets. In these simulations the satellites, with equal masses, were located in equilibrium positions found by Slo & Yoder (1988). The results of these simulations have shown that depending on the eccentricity of the particles and the satellites the ring can present azimuthal and radial variations. Although these variations can explain some clumps, the simulations also show that most of the features are temporary ones, specially whe the oblateness of the planet is included. The results for the Encke gap ringlets have shown that the presence of moonlets, as predicted by Ferrari & Brahic (1997), can caude the destruction of the ringles in about 200 yrs. For the system formed by the F ring, Prometheus and Pandora was verified that this system is considerably sensible to the initial conditions; some particles can stay in a horseshoe orbit for a short period of time for particular initial conditions. This result is in agreement with recent works with show that the two satellites, Prometheus and Pandora, are in a chaotic motion. Complementary to this study, the equilibrium positions for the particles and for the satellites (with unequal masses) were obtained. Thi analysis was based on the circular retricted thrre-body problem. Depending on the size and the number of the satellites present in the ring, the location of these positions can have a significant change. These equilibrium positions can help to locate moonlets in narrow planetary rings.
Hypothetical moonlets are claimed to be reponsible for a variety of structures found in narrow planetary rings. The Encke gap ringlets and theF ring of Saturn present strange features, such as clumps and kinks, wich can be related to the presence of these hypothetical moonlets. In an attempt to understand the behavior og the ring particles under the effects of these embedded moonlets, numerical simulations have been carried out for a system composed of two and three moonlets. In these simulations the satellites, with equal masses, were located in equilibrium positions found by Slo & Yoder (1988). The results of these simulations have shown that depending on the eccentricity of the particles and the satellites the ring can present azimuthal and radial variations. Although these variations can explain some clumps, the simulations also show that most of the features are temporary ones, specially whe the oblateness of the planet is included. The results for the Encke gap ringlets have shown that the presence of moonlets, as predicted by Ferrari & Brahic (1997), can caude the destruction of the ringles in about 200 yrs. For the system formed by the F ring, Prometheus and Pandora was verified that this system is considerably sensible to the initial conditions; some particles can stay in a horseshoe orbit for a short period of time for particular initial conditions. This result is in agreement with recent works with show that the two satellites, Prometheus and Pandora, are in a chaotic motion. Complementary to this study, the equilibrium positions for the particles and for the satellites (with unequal masses) were obtained. Thi analysis was based on the circular retricted thrre-body problem. Depending on the size and the number of the satellites present in the ring, the location of these positions can have a significant change. These equilibrium positions can help to locate moonlets in narrow planetary rings.
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Palavras-chave
Sistema solar, Satelites - Orbitas
Como citar
SILVA, Priscila Alves da. Dinâmica de uma partícula coorbital a um sistema de satélites. 2003. 167 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Engenharia de Guaratinguetá, 2003.