Atmospheres and magnétospheres of the giant planets


At LPAP, we are particularly interested in the aurorae of Jupiter and Saturn in the ultraviolet range. We work primarily with images and spectra from the Hubble Space Telescope and the Cassini spacecraft (orbiting Saturn). These analyzes are often Jupiter ultraviolet aurora supplemented by models or by other observations, either from the ground (infrared), from space observatories (X-rays) or from other spacecraft exploring these planets (eg. Galileo , Ulysses, New Horizons , etc.).

Planets cannot be reduced to large spheres of rock, ice or gas. Their area of influence extends well beyond their upper atmosphere, through their gravitational attraction and their magnetic field. This influence is particularly striking for the gas giants such as Jupiter and Saturn. Their colossal mass allows them to harbor a series of satellites around them, some of which (Ganymede around Jupiter and Titan around Saturn) are even larger than Mercury. The "bubble" controlled by the magnetic field of Jupiter, called the magnetosphere, is so large that it would look wider than the Moon if one could see it with naked eyes from Earth.
Magnetospheres are mostly populated with charged particles (electrons and ions) forming a tenuous plasma. Nevertheless, this plasma may still host violent phenomena, resulting in the acceleration of these charged particles towards the polar regions of the planet. When these particles precipitate into the upper atmosphere, the impact causes light emission, called aurorae.

At LPAP, we are particularly interested in the aurorae of Jupiter and Saturn in the ultraviolet range. We work primarily with images and spectra from the Hubble Space Telescope and the Cassini spacecraft (orbiting Saturn). These analyzes are often Jupiter ultraviolet aurora supplemented by models or by other observations, either from the ground (infrared), from space observatories (X-rays) or from other spacecraft exploring these planets (eg. Galileo , Ulysses, New Horizons , etc.).

The studies carried out at LPAP address various topics such as the phenomena from which the aurorae originate (eg. magnetic reconnection, satellite-magnetosphere interactions, etc.), the particle acceleration mechanisms and the characteristics of the upper atmosphere, not to mention the magnetic field of these planets. Finally, we are also deeply involved in the most recent exploration missions dedicated to Jupiter and its satellites, namely: Juno (NASA), orbiting around Jupiter since 2016, and JUICE (ESA), whose launch is due for 2022.

Juno Mission

HST campaign

Mission Cassini

Contact
Denis GRODENT

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