Adaptação do integrador Rebound para o estudo de anéis planetários
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Data
2019-03-11
Autores
Siqueira, Patrícia Buzzatto [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O estudo dos anéis planetários pode ser usado como laboratório para a compreensão do processo de formação e dinâmica planetária. Anéis planetários são formados por partículas pequenas que sofrem a ação de diversas forças, além da força gravitacional. O estudo da dinâmica dos anéis pode ser abordado através de simulações numéricas para o problema de N-corpos. Neste trabalho apresentamos a adaptação do pacote REBOUND (Rein & Liu, 2012) através da inclusão de forças perturbativas para estudar a dinâmica de anéis planetários. Uma fonte de perturbação de origem gravitacional é devida ao formato não esférico do planeta, que pode ser representado com precisão até a expansão do potencial do termo J6. Além dessa, as principais são a força eletromagnética e a pressão de radiação solar. Também atuam forças de arrasto, como o de Poynting-Robertson e, eventualmente, as forças devido a atmosfera e do plasma. Embora sejam mais fracas, essas forças alteram a energia orbital das partículas e dominam a dinâmica em longos períodos de tempo. Abordamos essas forças através do REBOUND e verificamos os principais efeitos de cada uma das forças, cuja força devido ao formato não esférico do planeta causa uma precessão na longitude do pericentro, enquanto a força eletromagnética causa uma regressão e que ambas combinadas contribuem uma com a outra alterando a taxa de variação da longitude do pericentro. Já a força da pressão de radiação altera o formato da órbita e as forças de arrasto diminuem o semi-eixo maior da partícula. A combinação de todos estes efeitos dificulta a análise do movimento orbital, dessa forma comparamos nossos resultados com outros métodos numéricos para a evolução orbital das partículas. Implementamos todas as forças citadas no REBOUND e para validar os métodos desenvolvidos analisamos a evolução orbital das partículas dos anéis em diversas ocasiões, comparando com resultados já publicados na literatura. Verificamos que os erros sistemáticos se mantiveram da ordem da precisão de máquina. Todos estes resultados estão de acordo com o que é apresentado na literatura e com a integração numérica das equações médias.
The study of planetary rings can be used as a laboratory for understanding the formation process and planetary dynamics. Planetary rings are composed by circumplanetary dusts that are disturbed by the action of diverse forces, besides the gravitational force. The study of ring dynamics can be approached through numerical simulations for the N-body problem. In this work we present the adaptation of the REBOUND (Rein & Liu, 2012) package by including perturbative forces to study the dynamics of planetary rings. A source of perturbation of gravitational origin is due to the non-spherical shape of the planet, which can be represented in relation to an expansion of the potential until the term J6. In addition, the major are the electromagnetic force and the solar radiation pressure. In addition, there are also dragging forces, such as the Poynting-Robertson and eventually the forces due to atmosphere and plasma, however they are weaker, but they change the orbital energy of the particles, and dominate the dynamics in long periods of time. We approach these forces through the REBOUND and verify that the planetary oblateness causes a precession of the longitude of the pericenter, while the electromagnetic force causes a regression, and that both combine to contribute with each other by changing the rate of variation of the pericenter. Already the force of the radiation pressure changes the shape of the orbit and the drag forces decrease the larger semi major axis of the particle. The combination of all these effects makes it difficult to analyze orbital motion, thus comparing our results with other numerical and analitical methods for the orbital evolution of the particles. We implemented all the forces mentioned above in REBOUND and to validate the developed methods we analyzed the orbital evolution of the ring particles on several systens comparing with results already published in the literature. We verified that the systematic errors were kept well below machine precision. All these results are in accordance with what is presented in the literature and with the numerical integration of the average equations
The study of planetary rings can be used as a laboratory for understanding the formation process and planetary dynamics. Planetary rings are composed by circumplanetary dusts that are disturbed by the action of diverse forces, besides the gravitational force. The study of ring dynamics can be approached through numerical simulations for the N-body problem. In this work we present the adaptation of the REBOUND (Rein & Liu, 2012) package by including perturbative forces to study the dynamics of planetary rings. A source of perturbation of gravitational origin is due to the non-spherical shape of the planet, which can be represented in relation to an expansion of the potential until the term J6. In addition, the major are the electromagnetic force and the solar radiation pressure. In addition, there are also dragging forces, such as the Poynting-Robertson and eventually the forces due to atmosphere and plasma, however they are weaker, but they change the orbital energy of the particles, and dominate the dynamics in long periods of time. We approach these forces through the REBOUND and verify that the planetary oblateness causes a precession of the longitude of the pericenter, while the electromagnetic force causes a regression, and that both combine to contribute with each other by changing the rate of variation of the pericenter. Already the force of the radiation pressure changes the shape of the orbit and the drag forces decrease the larger semi major axis of the particle. The combination of all these effects makes it difficult to analyze orbital motion, thus comparing our results with other numerical and analitical methods for the orbital evolution of the particles. We implemented all the forces mentioned above in REBOUND and to validate the developed methods we analyzed the orbital evolution of the ring particles on several systens comparing with results already published in the literature. We verified that the systematic errors were kept well below machine precision. All these results are in accordance with what is presented in the literature and with the numerical integration of the average equations
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Palavras-chave
Planetas - Órbitas, Anéis de armazenamento, Gravitação, Anéis planetários, Forças perturbativas, Achatamento, Radiação solar, Eletromagnética, Planetary rings, Disturbing forces, Oblateness, Solar radiation, Electromagnetic.