Juin 27 @ 11 h 00 min – 12 h 00 minSéminaire
Juno is currently on an elliptical and polar orbit around Jupiter, since July 2016, and has successfully gathered data during 12 perijoves sequences. Juno offers a fantastic opportunity to study Jupiter’s magnetosphere and its spectacular auroral emissions, which can be seen as a window screen of the entire Jovian magnetosphere. The Juno Ultraviolet Spectrograph (UVS) is a UV spectrograph with a bandpass spanning 70 to 205 nm and is designed to characterize Jupiter’s UV emissions. We present a brief overview on Juno-UVS operations. We then present observations of the Io footprints as seen by UVS. The Io footprints are a characterization of the complex magnetodynamic interaction at Io and modulated by the inner magnetosphere of Jupiter. Previous observations taken with the Hubble Space Telescope allowed the characterization of the footprints as a function of Io’s centrifugal latitude, despite observational bias that Earth-based observers are subject to. Juno’s unique vantage point in the Jovian system removes these biases allowing UVS access to the full range of Io’s varying centrifugal latitude and all possible local time geometries.
Sep 12 @ 11 h 00 min – 12 h 00 minSéminaire
Solar twins are stars that have spectra very similar to the Sun, with effective temperature, surface gravity and metallicity around solar values. This similarity allow us to determine very precise stellar parameters and chemical abundances (~0.01 dex), that makes possible the investigation of effects that can imprint subtle changes in the chemical pattern of a star, for example planet engulfments.Also, the high precision atmospheric parameters that can be derived for these objects permit us a reliable determination of their ages using a traditional isochrone method which, in association with the abundances determination, can bring many benefits to studies of the chemical evolution of the Galaxy.I will talk about the differential method, and discuss about past and recent works on the planet-host star chemical connection and the chemical evolution of the Galaxy.
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