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We use particle and magnetic field data from the Ion and Neutral Camera (INCA) and the magnetometer (MAG) onboard Cassini to detect and examine an energetic particle event that occurred upstream from the Saturnian bow shock during DOY 229/2007. The energetic (>100 keV) O+ ions are observed only when the Interplanetary Magnetic Field (IMF) connects the spacecraft with the planetary bow shock. We provide strong evidence showing the magnetospheric origin of the observed ions: (1) We detect singly ionized oxygen (O+) which is not resident of the solar wind, (2) the particle pitch angle distribution indicates that the ions travel along the field line connecting the spacecraft to the bow shock and (3) the ion intensity increases are observed only during the periods of magnetic connection to the bow shock. Our results show that the Saturnian dayside magnetosphere is not as sealed as thought to be, but can -under certain circumstances- allow high energy magnetospheric plasma to leak into the nearby solar wind and further in space.

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: John Lacy. Vita. Includes bibliographical references. Also available from UMI.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Orientador: Ernesto Vieira Neto / Coorientador: Stéfan Renner / Banca: Silvia Maria Giuliatti Winter / Banca: Rafael Sfair de Oliveira / Banca: Elbert Einstein Nehrer Macau / Banca: Nelson Callegari Júnior / Resumo: Desde 2004, as imagens obtidas pelas câmeras da sonda Cassin têm revelado a existência de vários pequenos satélites no sistema de Saturno. Três desses pequenos satélites estão dentro de arcos de partículas. Enquanto Aegaeon, Methone e Anthe e seus arcos são conhecidos por estarem em ressonância de corrotação 7:6, 14:15 e 10:15, respectivamente, com Mimas, a origem desses arcos é desconhecida. Logo, este trabalho investiga um possível processo de captura em ressonância de corrotação, que envolve o aumento da excentricidade de um satélite perturbador. Assim, através de simulações numéricas e estudos analíticos, nós mostramos um cenário que a excitação da excentricidade de Mimas poderia capturar partículas em ressonância de corrotação 7:6 14:15 e 10:11 com Mimas, fornecendo uma possível explicação para a origem dos arcos de Saturno. Outro objetivo deste trabalho é analisar uma possível região de origem de Aegaeon. Pois, há uma possibilidade de que a pequena lua Aegaeon tenha sido formada em outra região do sistema de Saturno diferente daquela que ela se encontra atualmente. Assim, também através de simulações numéricas e estudos analíticos, verificamos se a perturbação de Jano e Epimeteu através da ressonância de corrotação e Lindblad na borda externa do anel A é responsável pela migração de objetos dessa borda / Abstract: Since 2004, the images obtained by the Cassini spacecraft on-board cameras have revealed the existence of several small satellites in Saturn system. Three of these small satellites are embedded in arcs of particles. While Aegaeon, Methone and Anthe and their arcs are known to be in 7:6, 14:15 and 10:11 corotation resonances, respectively with Mimas, their origin remains unknown. This work investigates one possible process for capturing bodies into a corotation resonance, which involves increasing in the eccentricity of the perturbing body. Therefore, through numerical simulations and analytical studies, we showed a scenario in which the excitation of Mimas' eccentricity could capture particles in 7:6, 14:15 and 10:11 corotation resonance. This is a possible explanation for the origin of the arcs. Another goal of this work is to analyze a region possible of Aegaeon's origin. Because, there's a possibility of which Aegaon moonlet has been formed in another region of Saturn's system different of that Aegaeon finds itself today. Thus, also through numerical simulations and analytical studies, we verified that perturbation of Jano and Epimeteu by corotation and Lindblad resonance in the outer edge of Saturn's A ring can be responsible by the migration of particles of this edge / Doutor

Made available in DSpace on 2014-06-11T19:25:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-07Bitstream added on 2014-06-13T19:12:15Z : No. of bitstreams: 1 cruz_c_me_guara.pdf: 3366150 bytes, checksum: 08b399d3f2ebf41ec982fc0b5becc024 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Neste trabalho propõe-se analisar a dinâmica do sistema Prometeu - Pandora - Anel F de Saturno, buscando soluções para alguns comportamentos anômalos observados em seus componentes. É realizada uma descrição geral, contextualizando este sistema dentro da estrutura de satélites e anéis de Saturno. A seguir, apresenta-se dados de interesse obtidos até o presente, a partir de observações realizadas pelas sondas espaciais Pioneer 11 e Voyager 1 e 2 e pelo Hubble Space Telescope, citando os pontos problemáticos deste sistema. A teoria necessária para a compreensão de alguns aspectos é colocada e discutida através de breves explanações. As principais publicações relacionadas ao tema são analisadas e comentadas, em ordem cronológica, demonstrando os avanços realizados no conhecimento deste sistema. Elabora-se uma proposta de investigação na tentativa de reproduzir os resultados mais importantes e através deles evoluir para a busca de novas informações que venham auxiliar no entendimento da dinâmica deste sistema, utilizando-se de ferramentas de simulação numérica, nas quais são acrescentados parâmetros e influências muitas vezes não-consideradas. Em trabalhos futuros, pretende-se realizar uma análise acurada dos resultados deste trabalho, introduzindo novas variáveis e elementos que possam enriquecer a teoria que vem sendo construída e que explique de maneira cada vez mais satisfatória os enigmas existentes no sistema Prometeu - Pandora - Anel F de Saturno. / In this work, we propose to analyze the dynamic of the Prometheus - Pandor - Saturn F ring system, searching for answers to the anomalous behavior of these bodies. We've made a general description, talking about this system and also about the ring and satellites structures of Saturn. Next, we show interesting data obtained until the moment from observations realized by the spacecrafts Pioneer 11 and 12 and Hubble Space Telescope, enumerating problematic points. We present the necessary theory to understand some aspects in evidence, discussing it through soon explanations. The main publications related to the topic are commented, in chronological order, showing advances in the understanding of this system. We've made an investigative offer to reproduce the most important results and through them develop new information to help the understanding of this dynamic system, using numerical simulations tools, in which we add new parameters and influences that wasn't consider. In future works, we'll try realize an accurate analyze of this work results, introducing new variables and elements to enrich the theory that has been built and to explain in a more clear manner the puzzle that exists in the Prometheus - Pandora - F ring system of Saturn.

Submitted by Nilton Carlos Santos Araujo null (nilcasr@gmail.com) on 2017-09-06T21:31:14Z No. of bitstreams: 1 teseNilton.pdf: 13643423 bytes, checksum: 0c49d4b6392db7c166aa5c18e501516b (MD5) / Approved for entry into archive by Monique Sasaki (sayumi_sasaki@hotmail.com) on 2017-09-11T19:47:37Z (GMT) No. of bitstreams: 1 araujo_ncs_dr_guara.pdf: 13643423 bytes, checksum: 0c49d4b6392db7c166aa5c18e501516b (MD5) / Made available in DSpace on 2017-09-11T19:47:37Z (GMT). No. of bitstreams: 1 araujo_ncs_dr_guara.pdf: 13643423 bytes, checksum: 0c49d4b6392db7c166aa5c18e501516b (MD5) Previous issue date: 2017-07-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Desde 2004, as imagens obtidas pelas câmeras da sonda Cassin têm revelado a existência de vários pequenos satélites no sistema de Saturno. Três desses pequenos satélites estão dentro de arcos de partículas. Enquanto Aegaeon, Methone e Anthe e seus arcos são conhecidos por estarem em ressonância de corrotação 7:6, 14:15 e 10:15, respectivamente, com Mimas, a origem desses arcos é desconhecida. Logo, este trabalho investiga um possível processo de captura em ressonância de corrotação, que envolve o aumento da excentricidade de um satélite perturbador. Assim, através de simulações numéricas e estudos analíticos, nós mostramos um cenário que a excitação da excentricidade de Mimas poderia capturar partículas em ressonância de corrotação 7:6 14:15 e 10:11 com Mimas, fornecendo uma possível explicação para a origem dos arcos de Saturno. Outro objetivo deste trabalho é analisar uma possível região de origem de Aegaeon. Pois, há uma possibilidade de que a pequena lua Aegaeon tenha sido formada em outra região do sistema de Saturno diferente daquela que ela se encontra atualmente. Assim, também através de simulações numéricas e estudos analíticos, verificamos se a perturbação de Jano e Epimeteu através da ressonância de corrotação e Lindblad na borda externa do anel A é responsável pela migração de objetos dessa borda. / Since 2004, the images obtained by the Cassini spacecraft on-board cameras have revealed the existence of several small satellites in Saturn system. Three of these small satellites are embedded in arcs of particles. While Aegaeon, Methone and Anthe and their arcs are known to be in 7:6, 14:15 and 10:11 corotation resonances, respectively with Mimas, their origin remains unknown. This work investigates one possible process for capturing bodies into a corotation resonance, which involves increasing in the eccentricity of the perturbing body. Therefore, through numerical simulations and analytical studies, we showed a scenario in which the excitation of Mimas’ eccentricity could capture particles in 7:6, 14:15 and 10:11 corotation resonance. This is a possible explanation for the origin of the arcs. Another goal of this work is to analyze a region possible of Aegaeon’s origin. Because, there’s a possibility of which Aegaon moonlet has been formed in another region of Saturn’s system different of that Aegaeon finds itself today. Thus, also through numerical simulations and analytical studies, we verified that perturbation of Jano and Epimeteu by corotation and Lindblad resonance in the outer edge of Saturn’s A ring can be responsible by the migration of particles of this edge.

Galileo's Eyeglass is a celebratory work for full orchestra with standard instrumentation commemorating Galileo Galilei's discoveries of the four largest moons of Jupiter and the rings of Saturn in 1610. The composition is approximately 14 minutes in duration, and although divided thematically into four parts, the music is continuous. The work exhibits primarily a blend of contemporary styles and compositional elements, yet it is rooted in traditional tonality; furthermore, the piece is interspersed with references to Galileo's life and times, including quotations of a toccata composed by the scientist's brother, Michelangelo Galilei, transcribed from lute tablature. Chapter 1 of Part 1 investigates relevant historical threads extracted from the backdrop of Galileo's life, from reflections on the events that shape the musical program, to the selection and preparation of the period music composed by Galileo's brother. Chapter 2 discusses specific musical components of Galileo's Eyeglass, including form, musical quotations, motivic and thematic material, harmonic language, orchestration, and notation. Chapter 3 examines the principal philosophical themes behind the composition, including expressions of victory of a life well lived in spite of many obstacles. Part 2 contains the orchestral score.

The Cassini spacecraft orbited Saturn for over 13 years and collected stellar occultations using an Ultraviolet Imaging Spectrograph (UVIS). Chord occultations were analyzed using autocorrelations at minimum ring plane radius to visualize the structure and correlation in the azimuthal direction. These particle tracking occultations cut a chord across the rings in the path of the star. By taking the autocorrelation of these chord occultations, 8 out of the 66 showed clumping within the first 3.0 km in azimuth, representing signs of a structure. Six of those occultations could be moonlets or propellers as their minimum ring plane radii are in the Propeller Belt region. The Fast Fourier Transform Power Spectrum of the autocorrelation was also taken, and 6 of the 8 had high peak power outputs at certain wavelengths. It is also observed that five of the occultations may contain self-gravity wakes.