In this Thesis, I explore transiting exoplanets: what we can learn from modeling their light curves, and what we can learn from their arrangement in planetary systems. I begin in Chapter 1 by briefly reviewing the history of transit modeling, from the earliest theoretical models of eclipsing binary stars to the models in current widespread use to model exoplanet transits. In Chapter 2, I model the transits of a sample of Kepler exoplanets with strong prior eccentricity constraints in order to derive correspondingly strong constraints on the density of their host stars, and find that the density constraints I derive are as precise as density constraints from asteroseismology if the transits are observed at high signal-to-noise. In Chapter 3, I apply the same methodology in reverse: using prior knowledge of the stellar density based on Gaia parallax measurements, I model the transits of twelve singly-transiting planets observed by K2 and derive constraints on their periods. In Chapter 4, I consider the general problem of deducing the shape of a transiting object from its light curve alone, which I term ``shadow imaging;'' I explore the mathematical degeneracies of the problem and construct shadow images to explain Dips 5 and 8 of Boyajian's Star. I next turn to multi-planet systems: in Chapter 5, I investigate the underlying multiplicity distribution of planetary systems orbiting FGK dwarfs observed by Kepler. I find that we can explain the multiplicities of these systems with a single Zipfian multiplicity distribution, without invoking a dichotomous population. In Chapter 6, I consider the arrangement of planets in those systems, and use neural networks inspired by models used for part-of-speech tagging in computational linguistics to model the relationship between exoplanets and their surrounding "context," i.e. their host star and sibling planets. I find that our trained regression model is able to predict the period and radius of an exoplanet to a factor of two better than a naive model which only takes into account basic dynamical stability. I also find that our trained classification model identifies consistent classes of planets in the period-radius plane, and that it is rare for multi-planet systems to contain a neighboring pair of planets from non-contiguous classes. In Chapter 7, I summarize these results and briefly discuss avenues for future work, including the application of our methods to planets and planetary systems discovered by TESS.

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No description available.

No description available.

Over two hundred extrasolar planets have been discovered to date with various methods. This thesis reports on searching for extrasolar planets and characterising them by simulating their atmospheres. We used open clusters as targets for deep transit searches, with specific emphasis on the University of St. Andrews Planet Search at the Isaac Newton Telescope. We reduced CCD photometry and described the algorithm we used to search for transits. We estimated the number of transits we expect from our data. We then reduced photometry for the open cluster NGC 6940. From that data we found 18 low-amplitude, short-duration events, though none are transiting planets. They are all eclipsing binary stars. However, our null result constrains the number of planets around M dwarfs, the most numerous stars in our sample. In order to characterise reflected light from extrasolar planets, we built a three-dimensional Monte Carlo based radiation transfer model of extrasolar planetary atmospheres. We detailed the input parameters of the model, and show results of various models, focusing especially on the fractal nature of the clouds of our models, because these are the first three dimensional radiation transfer models of extrasolar planet atmospheres. We found very low geometric albedos in our simulations. Using data specific to the transiting planet HD 209458b, we built a model atmosphere with Rayleigh-scattering hydrogen gas and clouds of enstatite and iron. We show in several models the rarity of a bright HD 209458b, and conclude with some explanations on why extrasolar planets are likely dark and not detected with reflected light.

Trata-se de investigação sobre fluxos comunicacionais urbanos de cunho ambiental, em busca dos \'trânsitos discursivos multidimensionais\' (CITELLI, 2012) operados nessa interface em direção à proatividade do cidadão. Multirreferencial é o lastro teórico sobre o qual nos apoiamos, incluindo saberes da Comunicação, da Educação e da Ciência Ambiental, com destaque para Citelli (2004, 2006, 2007, 2008, 2011, 2012), Orozco Gómez (2006), Martín- Barbero (2003, 2009), Soares (2000, 2011), Castells (2003, 2011), Matos (2006, 2009, 2011), Jacobi (2000, 2008, 2010), Loureiro (2004, 2007, 2008), Berna (2010), Pontuchska e Krasilchik (2006), Ribeiro (2004) e Novicki (2002, 2007). Nosso objetivo geral é verificar e analisar os fluxos comunicacionais que conferem (ou não) permeabilidade à Comunicação Ambiental, com vista à construção de sentido e ação afirmativa em região paulistana com problemas ambientais (o distrito Vila Medeiros, São Paulo, capital). O método de Lopes (2004, 2005, 2010) para pesquisa em Comunicação, com seus níveis e fases, associado a contribuições do método Estudo do Meio (Pontuchska, 2011) conduzem o trabalho. A recolha de dados de campo se deu por meio de observação direta e registro fotográfico in loco, entrevistas com servidores públicos municipais vinculados às áreas ambiental e de Saúde Pública na região, bem como por meio de questionários aplicados aos moradores do referido distrito. Trabalhamos, quanto aos respondentes dos questionários, com uma amostra estratificada e não probabilística, constituída de 179 sujeitos de pesquisa: 57 adultos, 62 jovens do ensino médio e 60 jovens do ensino fundamental. Os resultados apontam para: a) lacunas em diversos fluxos de comunicação envolvendo o poder público e os cidadãos, os cidadãos entre si e os cidadãos e as demais instituições/entidades no lócus de pesquisa; b) necessidade de empoderamento dos cidadãos para questionar representações sedimentadas que funcionam como motor-reverso face às urgências de cuidado ambiental urbano verificadas no distrito analisado. / This research treats about urban communications flows environment-related, searching for the \'multidimensional discursive transits\' (CITELLI, 2012) that operate in this interface, seeking for the proactivity of the citizen. Multireferential is the theoretical coverage on which we support , including knowledge of Communication, Education and Environmental Science , highlights for Citelli (2004, 2006, 2007, 2008, 2011, 2012), Orozco Gómez (2006), Martín-Barbero (2003,2009), Soares (2000, 2001), Castells (2003, 2011), Matos (2006, 2009, 2011), Jacobi (2000, 2008, 2010), Loureiro (2004, 2007, 2008), Berna (2010), Pontuchska e Krasilchik (2006), Ribeiro (2004) e Novicki (2002, 2007). Our general objective is verify and analyze the communicational flows that gives (or not) permeability to the Environmental Communication, aiming the construction of meaning and affirmative action on São Paulo´s region with environmental problems (Vila Medeiros´s District, São Paulo, capital). The Lopes´s method (2004, 2005, 2010) for researches about Communication, with their levels and phases, associated with the contributions of Study of the Environment Method (Pontuchska, 2011) leads the study. The collection of the field data was through direct observation and photographic record in loco, interviews with municipal public servants bound with the environmental areas and Public Health in the region, well as through questionnaires, applied to the residents of the referred district. We work with regard to the respondents, with a non probabilistic stratified sample, constituted of 179 research subjects: 57 adults, 62 high school students and 60 elementary school students. The results points to a) gaps in various communication flows involving the government and the citizens, the citizens themselves and the citizens and the others institutions/entities in the locus of the research; b) need of empowerment of the citizens for questioning public representations sedimented that works as reverse-motor in view of the urgencies of urban environmental care verified on the analyzed district.

Dedicamos estudar neste trabalho o ofício da música nas vilas de Recife e Olinda ao longo do século XVIII. Neste caso, partindo de um olhar etnomusicológico de um espaço-tempo histórico e com atenção aos conceitos "nativos", propomos compreender a partir dos esboços das trajetórias de cinco músicos e de suas redes de relações o exercício profissional dos músicos e suas práticas musicais no contexto sociocultural das vilas de Recife e Olinda. Assim, conseguimos perceber a existência de diversas compatibilidades culturais e estético/performáticas da música com o centro do Império Português, resultante dos frequentes trânsitos e comunicações dos músicos dos dois lados do Atlântico, o que justifica a frequente atuação na metrópole dos músicos transitados da capitania de Pernambuco para com uma forte rede clientelar lisboeta ao longo do século XVIII, composta pelos ricos comerciantes e mercadores, mas também pela alta nobreza e pelo alto clero. No espaço de Recife e Olinda propomos compreender como os músicos se articulavam em torno dos compartilhamentos, práticas e exercício profissional da música em uma sociedade altamente hierarquizada como a do Antigo Regime. Assim, percebemos a existência de uma "hierarquia do ofício da música", resultante não apenas do acúmulo de conhecimento prático e especulativo, mas também das redes clientelares constituída por esses músicos. Essas redes clientelares, fomentadoras inclusive dos trânsitos dos músicos à metrópole, eram responsáveis também por um subjetivo controle do ofício da música em grande parte dos setecentos, ao mediar a atuação dos músicos sob suas proteções. Entretanto, na segunda metade do século XVIII, ocorreu um aumento no número de músicos e uma redução dos serviços para com essas redes clientelares, decorrente das políticas econômicas das reformas pombalinas, o que resultou na necessidade da organização e controle do ofício da música na vila do Recife, acontecimentos que impulsionaram a constituição da Irmandade de Santa Cecília do Recife. Assim, ao construirmos os esboços das cinco trajetórias com suas redes de relações, tendo atenção ao contexto sociocultural desses músicos, conseguimos extrair e aprofundar questões subjetivas de possíveis práticas normativas musicais e sociais, possibilitando contribuir e avançar nos estudos musicológicos brasileiros, no sentido de uma maior compreensão dos músicos e das práticas musicais setecentistas da América Portuguesa. / This thesis studies the music craft in the villages of Recife and Olinda throughout the 18th century. Departing from an ethnomusicological perspective on this social space allied with an attention to "native" concepts, we propose to cover the trajectories of five musicians and their professional networks as well as their musical practices in the sociocultural context of these colonial villages. Thus, we can perceive the coexistence of diverse cultural and performative compatibilities of these musical practices with the center of the Portuguese Empire, as a result of the frequent transits and communications of musicians on both sides of the Atlantic. These transits clarifies the frequent presence in the metropolis of musicians transited from the captaincy of Pernambuco tied to a strong clientele composed of local wealthy merchants and merchants, but also tied to the high nobility and high clergy in Lisbon. In the space of Recife and Olinda we propose to understand how the musicians were articulated around the shares, practices and professional exercise of the music in the highly hierarchized society of the Ancien Régime. Thus, we perceive the existence of a "hierarchy of the music craft", resulting not only from the accumulation of practical and speculative knowledge, but also from the clientelistic networks constituted by these musicians. These patronage networks, including the transits of the musicians to the metropolis, were also responsible for a subjective control of the music trade in most of the seven hundred, in mediating the performance of the musicians under their protections. However, in the second half of the eighteenth century, there was an increase in the number of musicians and a reduction of services to these patronage networks, resulting from the economic policies of the Pombaline reforms, which resulted in the need to organize and control the music craft in the village of Recife, events that resulted in the formation of the Brotherhood of Santa Cecilia of Recife. Thus, in constructing the sketches of the five trajectories with their networks of relationships, taking into account the sociocultural context of these musicians, we were able to extract and deepen subjective questions of possible musical and social normative practices, making possible to contribute and advance in Brazilian musicological studies, towards a greater understanding of musicians and eighteenth-century musical practices in Portuguese America.

Flows, instabilities, and magnetism play significant roles in the internal and atmospheric dynamics of objects ranging from the smallest exoplanets to the largest stars. These phenomena are governed by the equations of magnetohydrodynamics (MHD), which link the flows and magnetic fields, and from which the operational parameters and growth rates of instabilities can be recovered. Here we present an overview of interesting phenomena (such as the internal dynamics of stellar and planetary objects, as well as instabilities which might operate within these environs), as well as computational techniques by which these phenomena might both be understood and analysed (through both ‘simplifications’ of the MHD equations and different numerical/computational approaches). We first present an investigation into the Heat-Flux-Driven Buoyancy Instability (HBI) within stellar and planetary atmospheres, considering both the parameter space it might operate within as well as its non-linear effects during said operation. We find that whilst the HBI may be able to play a role in Solar, stellar and planetary atmospheres, it is likely to be quite limited in scope, only operating within small regions. However, its dramatic consequences for heat transport in the non-linearly evolved state, and the prospects that it may operate outside the narrow regimes that our analytical analysis suggested, suggest that it may merit further study. This is followed with a discussion of a method by which the surface flows of exoplanets might be measured: The Rossiter-Mclaughlin Effect at Secondary Eclipse (RMse). We formulate the effect, showing that the formalism is identical to the traditional Rossiter-Mclaughlin effect, albeit in a different frame (a planet transiting a star becomes a star transiting a planet), and consider its observational implications: the effect should be observable for the brightest planet hosting stars using upcoming 40m-class telescopes (i.e.E-ELT). We finish with a series of 3D anelastic simulations of fully convective stars, designed to investigate how the internal flows are affected by varying stellar parameters, as well as a possible link between residual entropy and differential rotation contours, and a method by which this link can be used (via the thermal wind equation - TWE) to extrapolate the internal rotation. We find a clear transition between ‘solar-like’ and ‘anti-solar’ internal dynamics, characterised in the meridional circulation, differential rotation, residual entropy, and angular momentum flux profiles. Furthermore we find that, whilst the alignment between residual entropy and differential rotation contours is somewhat varied, the resultant extrapolation, via the TWE, produces a generally good fit to the differential rotation contours, suggesting a general robustness to the theory.

Trata-se de investigação sobre fluxos comunicacionais urbanos de cunho ambiental, em busca dos \'trânsitos discursivos multidimensionais\' (CITELLI, 2012) operados nessa interface em direção à proatividade do cidadão. Multirreferencial é o lastro teórico sobre o qual nos apoiamos, incluindo saberes da Comunicação, da Educação e da Ciência Ambiental, com destaque para Citelli (2004, 2006, 2007, 2008, 2011, 2012), Orozco Gómez (2006), Martín- Barbero (2003, 2009), Soares (2000, 2011), Castells (2003, 2011), Matos (2006, 2009, 2011), Jacobi (2000, 2008, 2010), Loureiro (2004, 2007, 2008), Berna (2010), Pontuchska e Krasilchik (2006), Ribeiro (2004) e Novicki (2002, 2007). Nosso objetivo geral é verificar e analisar os fluxos comunicacionais que conferem (ou não) permeabilidade à Comunicação Ambiental, com vista à construção de sentido e ação afirmativa em região paulistana com problemas ambientais (o distrito Vila Medeiros, São Paulo, capital). O método de Lopes (2004, 2005, 2010) para pesquisa em Comunicação, com seus níveis e fases, associado a contribuições do método Estudo do Meio (Pontuchska, 2011) conduzem o trabalho. A recolha de dados de campo se deu por meio de observação direta e registro fotográfico in loco, entrevistas com servidores públicos municipais vinculados às áreas ambiental e de Saúde Pública na região, bem como por meio de questionários aplicados aos moradores do referido distrito. Trabalhamos, quanto aos respondentes dos questionários, com uma amostra estratificada e não probabilística, constituída de 179 sujeitos de pesquisa: 57 adultos, 62 jovens do ensino médio e 60 jovens do ensino fundamental. Os resultados apontam para: a) lacunas em diversos fluxos de comunicação envolvendo o poder público e os cidadãos, os cidadãos entre si e os cidadãos e as demais instituições/entidades no lócus de pesquisa; b) necessidade de empoderamento dos cidadãos para questionar representações sedimentadas que funcionam como motor-reverso face às urgências de cuidado ambiental urbano verificadas no distrito analisado. / This research treats about urban communications flows environment-related, searching for the \'multidimensional discursive transits\' (CITELLI, 2012) that operate in this interface, seeking for the proactivity of the citizen. Multireferential is the theoretical coverage on which we support , including knowledge of Communication, Education and Environmental Science , highlights for Citelli (2004, 2006, 2007, 2008, 2011, 2012), Orozco Gómez (2006), Martín-Barbero (2003,2009), Soares (2000, 2001), Castells (2003, 2011), Matos (2006, 2009, 2011), Jacobi (2000, 2008, 2010), Loureiro (2004, 2007, 2008), Berna (2010), Pontuchska e Krasilchik (2006), Ribeiro (2004) e Novicki (2002, 2007). Our general objective is verify and analyze the communicational flows that gives (or not) permeability to the Environmental Communication, aiming the construction of meaning and affirmative action on São Paulo´s region with environmental problems (Vila Medeiros´s District, São Paulo, capital). The Lopes´s method (2004, 2005, 2010) for researches about Communication, with their levels and phases, associated with the contributions of Study of the Environment Method (Pontuchska, 2011) leads the study. The collection of the field data was through direct observation and photographic record in loco, interviews with municipal public servants bound with the environmental areas and Public Health in the region, well as through questionnaires, applied to the residents of the referred district. We work with regard to the respondents, with a non probabilistic stratified sample, constituted of 179 research subjects: 57 adults, 62 high school students and 60 elementary school students. The results points to a) gaps in various communication flows involving the government and the citizens, the citizens themselves and the citizens and the others institutions/entities in the locus of the research; b) need of empowerment of the citizens for questioning public representations sedimented that works as reverse-motor in view of the urgencies of urban environmental care verified on the analyzed district.

On considère d'abord le problème de trois corps. En première approximation, il est étudié le cas d'une étoile binaire qui perturbe le mouvement d'une troisième étoile liée gravitationnellement au système, mais qui se trouve éloignée. Ces perturbations peuvent imiter le mouvement réflexe d'une étoile qui possède une planète provoquant une fausse détection planétaire par des méthodes astrométriques ou de vitesse radiale. Ensuite, on considère un problème de trois corps constitué par une étoile avec deux planètes; on étudie les perturbations produites dans ce type de systèmes et on examine leur influence dans la détection de planètes par la méthode de transits: les changements dans le temps d'arrivée du signal et dans la durée et la profondeur des transits. On étudie, du point de vue photométrique, la possibilité que des phénomènes d'activité stellaire tels que les taches puissent imiter la signature photométrique d'un transit. La forme et la taille de la diminution du flux stellaire produite par une tache est en général différente d'un transit, mais ils existent certaines configurations où les taches peuvent imiter la forme d'un transit rasant. De l'autre côté, on étudie la photométrie planétaire pour considérer non seulement la possibilité de mesurer la lumière réfléchie par une planète, sinon les phénomènes photométriques mutuels qui se produisent dans une système planète-compagnon: les éclipses et les ombres projetées sur les surfaces. Les méthodes mathématiques ainsi développés permettent d'étudier numériquement en détail la signature photométrique des transits. Finalement, une grande partie de la thèse a été dédiée à l'analyse de données fournies par la mission CoRoT consacrées à la recherche de planètes extra-solaires. Quatre fois par an, le satellite fournit dix mille courbes de lumière qu'il faut traiter pour éliminer le bruit instrumental ainsi que la variabilité stellaire. Ensuite, il faut fouiller les courbes à la recherche des transits planétaires et les caractériser pour pouvoir réaliser des observations photométriques et spectroscopiques depuis le sol et obtenir la masse de l'objet en transit. Dans les systèmes où il a été trouvé une planète, on étudie les possibles perturbations dans le temps d'arrivée du signal.