Planetary rings and astrophysical disk physics

Séminaire IPAG de Pierre-Yves Longaretti (IPAG), jeudi 2 février 2017 à 11h00, IPAG seminar room

Disks are among the most common and most studied objects in astrophysics. At first sight, all disks are superficially similar, as the central object dominates their gross geometric and physical characteristics. However, this apparent uniformity is lost at a closer look. Astrophysical disks differ considerably in their microphysical and thermodynamic properties, and a host of weaker dynamical effects provide for a wide spectrum of dynamical phenomena and control their long term evolution.

Among these, our solar system planetary rings are quite exceptional. Thanks to their (relative) proximity, they have been observed in situ, first by the two Voyager missions in the 1980s, and, in the case of Saturn’s rings, by the Cassini probe that has now been orbiting the planet for more than a decade. These missions have provided an unprecedented level of details on the structure of the major ring systems, as well as significant constraints on their dynamics.

The talk will review our present state of knowledge of the dynamics of the major rings, with a focus on processes relevant in other astrophysical disks, most notably, YSO and debris disks. Among the processes of general interest directly observed in rings, one can mention the physics of self-gravitational waves and wakes, gap formation and confinement, and more generally, the various forms of disk/satellite (disk/planet) interactions.