Lindblad torque

Lindblad torque (named for Swedish astronomer Bertil Lindblad) is a torque on an orbiting body due to orbital resonances known as Lindblad resonances. These are of interest in the dynamics of circumstellar disks, including planets or planetoids, orbiting within a (gas) Keplerian disk. This torque and corotation torque are the contributers to a planet's Type I migration. Lindblad resonances (inner and outer) affect stellar dynamics within disk galaxies as well.