Dinâmica dos pequenos corpos de Netuno e o sistema Kepler-90
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2021-12-01
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Universidade Estadual Paulista (Unesp)
Resumo
O sistema de anéis e satélites de Netuno foi descoberto (e o sistema de arcos de Netuno confirmado) durante a passagem da sonda espacial Voyager 2 em 1989 (SMITH et al., 1989). O sistema interno de Netuno possui um conjunto de sete satélites denominados Naiade, Thalassa, Despina, Galatea, Larissa, Hipocampo, Proteus e Tritão, além dos anéis Galle, Le Verrier, Lassell, Arago, anel coorbital de Galatea, e Adams. Neste trabalho analisamos a estabilidade da região interna do sistema de Netuno através dos mapas de difusão para um conjunto de partículas-teste sob a influência gravitacional de todos os satélites do sistema interno. Forças dissipativas como a pressão de radiação solar (para partículas micrométricas) e o arrasto devido ao plasma serão incluídas no estudo dos anéis. As partículas estarão inicialmente em órbitas excêntricas, onde serão assumidos os valores de excentricidade geométrica no intervalo de 0 a 0.04. O anel de Galle é o mais próximo ao planeta e está longe dos satélites, sendo localizado em uma região estável. Enquanto a borda interna do anel de Lassel (com largura igual a 4000 km) apresenta uma região estável dependente do valor da excentricidade. O mesmo ocorre com os anéis Le Verrier e Adams, esses anéis são estáveis para pequenos valores de excentricidade. Esses anéis podem sobreviver à perturbação dos satélites próximos para valores de e < 0.012. Quando a força de radiação solar é considerada, os anéis compostos por partículas de 1 µm apresentam um tempo de vida de 10⁴ anos, enquanto as partículas maiores (10 µm de raio) podem sobreviver até 10⁵ anos. Observações feitas pelo Telescópio Kepler durante quatro anos mostraram que existem sistemas multi- planetários, cujos planetas estão distribuídos de forma similar ao Sistema Solar (BORUCKI et al., 2010; BORUCKI et al., 2011). O sistema Kepler-90 apresenta um conjunto formado por oito planetas b, c, i, d, e, f , g e h, em distância crescente da estrela. Os planetas g e h são similares aos gigantes gasosos, enquanto os planetas d, e e f são similares às superterras. A configuração do sistema é similar ao Sistema Solar, pequenos planetas estão próximos e os maiores estão distantes da estrela, embora o planeta externo tenha uma distância orbital igual a 1 UA. Através da análise de frequência e simulações numéricas de longo período, analisamos a estabilidade das órbitas dos planetas para um conjunto de parâmetros, como a massa, o semieixo maior e excentricidade. Realizamos simulações numéricas para analisar três diferentes intervalos de excentricidade: o primeiro intervalo é de 0 a 1×10^−3 , o segundo intervalo é de 1×10^−3 a 1×10^−2 e o terceiro intervalo é de 1×10^−2 a 1×10^−1 . Os valores de excentricidade, argumento do pericentro, longitude do nodo ascendente e longitude média foram escolhidos aleatoriamente em cada intervalo de excentricidade. Os resultados mostram que os planetas com excentricidades que pertencem aos dois primeiros intervalos são estáveis, enquanto a maioria dos planetas com excentricidade 1×10^−2 a 1×10^−1 são ejetados do sistema. A variação da excentricidade dos planetas nos dois primeiros intervalos indicam que o planeta h é dominante, sendo importante para a estabilidade do sistema Kepler-90. Identificamos as ressonâncias de movimento médio 5:4 e 3:2 dos planetas b e c e g e h, respectivamente. Simulamos numericamente um conjunto de partículas nos "sistemas Kepler-90", através do mapa de difusão, onde identificamos quatro regiões estáveis entre as órbitas dos planetas c-i, i-d, d-e, e além da órbita do planeta h sendo identificadas como regiões 1, 2, 3 e 4, respectivamente. Os platôs associados às ressonâncias são identificadas com o planeta i e o planeta h. Os resultados mostraram que as partículas-teste estão em ressonância de movimento médio2:3, 5:6, 7:8 e 9:10 com o planeta i, e 1:2, 3:4, 3:5, 3:7 e 3:8 com planeta h.
Neptune rings and small satellites system was discovered during the passage of Voyager 2 in 1989. The Neptune inner system has a cluster of seven satellites Naiade, Thalassa, Despina, Galatea, Larissa, Hippocampus, Proteus, and Triton and the rings Galle, Le Verrier, Lassell, Arago, Galatea’s coorbital, and Adams. In this work we analyze the stability of the inner region of the Neptune system through diffusion maps for a set of test particles under the gravitational influence of all satellites. Dissipative forces such as the solar radiation force (for micrometric particles) and the drag due to the plasma are included in the study of the rings. The particles in both cases are initially in eccentricity orbits, the geometric eccentricity values range in the interval from 0 to 0.04. The Galle ring, which is close to the planet and away from the inner satellites, is located in a stable region. Whereas, the inner edge of the Lassel ring (width of about 4000 km) is in a stable region that depends on the value of the eccentricity. Le Verrier and Adams rings also are stable for small values of the eccentricity. These rings can survive for the perturbation of the satellites for values of e < 0.012. When the solar radiation force is included, rings composed of 1 µm particles have a lifetime of 10⁴ years, while larger particles (10 µm radius) can survive up to 10⁵ years. Observations performed by the Kepler Telescope over four years have shown that multi-planetary systems exist, whose planets are distributed similar to our Solar System (BORUCKI et al., 2010; BORUCKI et al., 2011). The Kepler-90 system has eight planets b, c, i, d, e, f , g and h, in increasing distance from the star. Planets g and h are similar to the gas giants, while planets d, e and f are similar to super-Earths. This system is similar to the Solar System, small planets are close and larger ones are away from the star, although the outer planet has an orbital distance equals to 1 UA. The frequency map analysis and long period numerical simulations are used to analyze the stability of the planets’ orbits, for a set of parameters such as, the mass, semi-major axis, and eccentricity. We perform numerical simulations to analyze three different intervals of eccentricity: the first interval is from 0 to 1×10^−3 , the second interval is from 1×10^−3 to 1×10^−2 , and the third interval is from 1×10^−2 to 1×10^−1 . The values of the eccentricity, argument of pericenter, longitude of the ascending node, and mean longitude were chosen randomly in each eccentricity interval. The results show that the planets with eccentricities belonged to the first two intervals are stable, while most of the planets with eccentricities 1×10^−2 to 1×10^−1 are ejected from the system. The eccentricity variation of the planets in the first two intervals indicate that the planet h is dominant in the systems being important for the stability of the Kepler-90 system. We identify the 5:4 and 3:2 mean motion resonances between planets b and c and g and h, respectively. We numerically simulated a set of particles in the "Kepler-90 systems", through diffusion maps. We identify four stable regions between the orbits of planets c-i, i-d, d-e, and beyond the orbit of planet h being identified as regions 1, 2, 3 and 4, respectively. The plateaus associated with the resonances are identified with planet i and planet h. The results showed that the test particles are in mean motion resonances 2:3, 5:6, 7:8 and 9:10 with planet i, and 1:2, 3:4, 3:5, 3:7 and 3:8 with planet h.
Neptune rings and small satellites system was discovered during the passage of Voyager 2 in 1989. The Neptune inner system has a cluster of seven satellites Naiade, Thalassa, Despina, Galatea, Larissa, Hippocampus, Proteus, and Triton and the rings Galle, Le Verrier, Lassell, Arago, Galatea’s coorbital, and Adams. In this work we analyze the stability of the inner region of the Neptune system through diffusion maps for a set of test particles under the gravitational influence of all satellites. Dissipative forces such as the solar radiation force (for micrometric particles) and the drag due to the plasma are included in the study of the rings. The particles in both cases are initially in eccentricity orbits, the geometric eccentricity values range in the interval from 0 to 0.04. The Galle ring, which is close to the planet and away from the inner satellites, is located in a stable region. Whereas, the inner edge of the Lassel ring (width of about 4000 km) is in a stable region that depends on the value of the eccentricity. Le Verrier and Adams rings also are stable for small values of the eccentricity. These rings can survive for the perturbation of the satellites for values of e < 0.012. When the solar radiation force is included, rings composed of 1 µm particles have a lifetime of 10⁴ years, while larger particles (10 µm radius) can survive up to 10⁵ years. Observations performed by the Kepler Telescope over four years have shown that multi-planetary systems exist, whose planets are distributed similar to our Solar System (BORUCKI et al., 2010; BORUCKI et al., 2011). The Kepler-90 system has eight planets b, c, i, d, e, f , g and h, in increasing distance from the star. Planets g and h are similar to the gas giants, while planets d, e and f are similar to super-Earths. This system is similar to the Solar System, small planets are close and larger ones are away from the star, although the outer planet has an orbital distance equals to 1 UA. The frequency map analysis and long period numerical simulations are used to analyze the stability of the planets’ orbits, for a set of parameters such as, the mass, semi-major axis, and eccentricity. We perform numerical simulations to analyze three different intervals of eccentricity: the first interval is from 0 to 1×10^−3 , the second interval is from 1×10^−3 to 1×10^−2 , and the third interval is from 1×10^−2 to 1×10^−1 . The values of the eccentricity, argument of pericenter, longitude of the ascending node, and mean longitude were chosen randomly in each eccentricity interval. The results show that the planets with eccentricities belonged to the first two intervals are stable, while most of the planets with eccentricities 1×10^−2 to 1×10^−1 are ejected from the system. The eccentricity variation of the planets in the first two intervals indicate that the planet h is dominant in the systems being important for the stability of the Kepler-90 system. We identify the 5:4 and 3:2 mean motion resonances between planets b and c and g and h, respectively. We numerically simulated a set of particles in the "Kepler-90 systems", through diffusion maps. We identify four stable regions between the orbits of planets c-i, i-d, d-e, and beyond the orbit of planet h being identified as regions 1, 2, 3 and 4, respectively. The plateaus associated with the resonances are identified with planet i and planet h. The results showed that the test particles are in mean motion resonances 2:3, 5:6, 7:8 and 9:10 with planet i, and 1:2, 3:4, 3:5, 3:7 and 3:8 with planet h.
Descrição
Palavras-chave
Mapa de difusão, Pressão de radiação solar, Sistema de Netuno, Kepler-90, Diffusion map, Pressure solar radiation, Netuno inner system