000005614 001__ 5614
000005614 005__ 20220125121612.0
000005614 037__ $$aCTALK-2022-0019
000005614 100__ $$aVan Hoolst, Tim 
000005614 245__ $$aThe rotation of Ganymede and Callisto
000005614 260__ $$c2021
000005614 269__ $$c2021-09-13
000005614 520__ $$aThe rotation rates of Ganymede and Callisto, the two largest satellites of Jupiter, are on average equal to their orbital mean motion but cannot be constant as a result of the varying gravitational torque exerted by Jupiter on the satellites. For a Keplerian orbit, the period of the torque and of the rotation variations is equal to the orbital period. Gravitational interaction with the other Galilean satellites and the Sun induces deviations from a purely Keplerian orbital motion, leading to changes in the gravitational torque of Jupiter on the satellites with respect to the mean Keplerian orbital motion and therefore to additional rotation variations. Here we discuss small variations from the average rotation on different time scales and assess the potential of using rotation as a probe of the interior structure. The ESA JUICE (JUpiter ICy moons Explorer) mission will measure the rotation and tides of Ganymede and Callisto in the early 30s, and will in particular very accurately determine those quantities for Ganymede during the orbital phase of the spacecraft around that satellite starting in 2032. We report on different theoretical aspects of the rotation for realistic models of the interior of the satellites, include tidal deformations and take into account the low-degree gravity field and topography of Ganymede and Callisto. We assess the advantages of a joint use of rotation and tides to constrain the satellite's interior structure, in particular its ice shell and ocean.
000005614 594__ $$aNO
000005614 700__ $$aBaland, Rose-Marie
000005614 700__ $$aBeuthe, Mikael 
000005614 700__ $$aCoyette, Alexis 
000005614 700__ $$aRivoldini, Attilio 
000005614 700__ $$aYseboodt, Marie
000005614 773__ $$tEuropean Planetary Science Congress 2021, online
000005614 8560_ $$fmarie.yseboodt@observatoire.be
000005614 85642 $$ahttps://meetingorganizer.copernicus.org/EPSC2021/EPSC2021-621.html
000005614 906__ $$aContributed
000005614 980__ $$aCTALKCONT