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Light propagating to a ground-based telescope passes through a region of varying refractive index, the turbulent atmosphere. And so even on top of the highest mountains, atmospheric turbulence limits the resolution of optical telescope, whatever their size, to approximately a 20cm telescope. Astronomers and engineers build ever larger telescope to collect more photons and study fainter and more distant object, but the only solutions to the atmospheric blurring is either to send telescope in space - an extremely expensive endeavor and offering limited flexibility -, or to develop dedicated systems correcting the atmospheric turbulence, so-called adaptive optics systems. Adaptive optics (AO) is a technique that flattens in real-time the distorted wavefront by measuring the residual errors and by controlling a deformable mirror. It improves the performance of ground-based telescopes up to the diffraction limit, which bring large im- provement in resolution and sensitivity. Over the last two decades, it has become a major technology in near-infrared astronomy and is favorable to many fields in astronomy : from the study of planetary systems, of stellar population, or the discovery of the supermassive black hole at the center of our galaxy. (Gilles Orban de Xivry, Implementation of an adaptive optics real-time control system based on a GPU for a 4-m class telescope, March 24 2017)

Adaptive Optics --- Telescope --- GPU --- Real-Time Control --- Ingénierie, informatique & technologie > Multidisciplinaire, généralités & autres

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L’interférométrie de nulling est une branche d’interférométrie. En exoplanétologie, elle permet « d’éteindre » une étoile afin de pouvoir observer d’éventuelles exoplanètes orbitant dans sa zone habitable. Ce type d’interférométrie apporte une meilleure résolution et un meilleur contraste ainsi que la possibilité d’étudier la composition chimique de l’atmosphère de jeunes exoplanètes.
Dans ce travail nous allons faire revivre le banc interférométrique CELINE afin de faire de l’interférométrie de nulling en bande L. Cette bande est intéressante car elle permettrait une meilleure étude de certaines bandes d’absorption de molécules présentes dans l’atmosphère d’exoplanète comme l’H2O, le CH4, le CO2, C2H2 et l’HCN.

Nulling interferometry --- L band nulling interferometry --- Infrared test bench --- Interférométrie de nulling --- Interférométrie de nulling en bande L --- Banc test infrarouge --- Physique, chimie, mathématiques & sciences de la terre > Aérospatiale, astronomie & astrophysique

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Theoretical works on the main auroral UV emission at Jupiter suggest that the dawn region must be more powerful than the dusk one. However, a study made with the Hubble Space Telescope (HST) has shown the opposite, with a dusk region about 3 times more powerful than the dawn one.

In this thesis, new data obtained with UVS, the UV spectra-imager onboard Juno, are used to create comprehensive brightness maps of the 39 first perijoves of the spacecraft in both hemispheres. These main emission is then isolated on these maps using 4 different methods. Finally, the dusk and dawn regions are found, and the emitted power in these regions are computed. A statistical analyses of the power thus obtained is performed to found if the results from the HST study could be retrieved.

Juno --- Jupiter --- Aurora --- UV --- Physique, chimie, mathématiques & sciences de la terre > Aérospatiale, astronomie & astrophysique