https://insu.hal.science/insu-03644938Fouvry, Jean-BaptisteJean-BaptisteFouvryIAP - Institut d'Astrophysique de Paris - INSU - CNRS - Institut national des sciences de l'Univers - SU - Sorbonne Université - CNRS - Centre National de la Recherche ScientifiqueUPMC - Université Pierre et Marie Curie - Paris 6Binney, JamesJamesBinneyPichon, ChristopheChristophePichonIAP - Institut d'Astrophysique de Paris - INSU - CNRS - Institut national des sciences de l'Univers - SU - Sorbonne Université - CNRS - Centre National de la Recherche ScientifiqueUPMC - Université Pierre et Marie Curie - Paris 6Self-gravity, Resonances, and Orbital Diffusion in Stellar DisksHAL CCSD2015diffusiongalaxies: evolutiongalaxies: kinematics and dynamicsgalaxies: spiralgravitationAstrophysics - Astrophysics of Galaxies[SDU] Sciences of the Universe [physics]Sorbonne Université, Gestionnaire HAL 42022-04-19 14:46:202023-07-03 17:09:222022-04-19 14:46:20enJournal articles10.1088/0004-637X/806/1/1171Fluctuations in a stellar system's gravitational field cause the orbits of stars to evolve. The resulting evolution of the system can be computed with the orbit-averaged Fokker-Planck equation once the diffusion tensor is known. We present the formalism that enables one to compute the diffusion tensor from a given source of noise in the gravitational field when the system's dynamical response to that noise is included. In the case of a cool stellar disk we are able to reduce the computation of the diffusion tensor to a one-dimensional integral. We implement this formula for a tapered Mestel disk that is exposed to shot noise and find that we are able to explain analytically the principal features of a numerical simulation of such a disk. In particular the formation of narrow ridges of enhanced density in action space is recovered. As the disk's value of Toomre's Q is reduced and the disk becomes more responsive, there is a transition from a regime of heating in the inner regions of the disk through the inner Lindblad resonance to one of radial migration of near-circular orbits via the corotation resonance in the intermediate regions of the disk. The formalism developed here provides the ideal framework in which to study the long-term evolution of all kinds of stellar disks.