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Our study of fast sodium jets from Io with the TRAPPIST-South telescope, spanning four months of observation from December 4, 2014 to March 31, 2015, begins with the acquisition and the reduction of the raw data. The optics of the telescope and the very powerful brightness of Jupiter produce artifacts on the images still present after calibration. We used several image processing methods to improve the signal-to-noise ratio and clean our reduced images in order to optimize the region where a jet would be located and to optimize our measurements. Among the fifteen observations nights, we observed six nights with sodium jets coming from Io. Then, we measured the length of all detected jets, extending over several Jovian radii, and the angle with the Jupiter-Io line. The night of December 4, 2014 is the most impressive, the extent of the detected jet is approximately seven Jovian radii. This first study allows us to improve the next observations with the ultimate aim of observing these jets and finally improve our understanding about them.

TRAPPIST --- Io --- Sodium jet --- Image processing --- observations --- Physique, chimie, mathématiques & sciences de la terre > Aérospatiale, astronomie & astrophysique

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The goal of this master’s thesis iw to better understand Mars and its complex processes and more specifcally to understand if the heterogeneity of the martian regolith may impact the degassing of volatile due to small impactors.To do so the increase of temperature as a result of impact energy is theoretically and numerically investigated. A modelisation of the increase of impact-induced temperature is proposed with an analytcial method : the Murnaghan equation of state.Then a comparison with a hydrocode (numerical method) is considered. To study the environmental effect, the evolution of the temperature following an impact for a martian year is calculated using the Crank-Nicholson method. The effect of the heterogeneity of the martian subsurface is then studied with the use of different plausible scenarii of different locations of interest on Mars. Finally, the results for each scenarii are compared with the depth of the ice table or the clathrate stability zone to assess its destabilization and thus degassing of methane.

Mars --- Impacts --- methane --- Regolith --- model --- 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