A dynamically young and perturbed Milky Way disk

Understand

The evolution of the Milky Way disk, which contains most of the stars in the Galaxy, is affected by several phenomena.

• For example, the bar and the spiral arms of the Milky Way induce radial migration of stars and can trap or scatter stars close to orbital resonances.
• External perturbations from satellite galaxies can also have a role, causing dynamical heating of the Galaxy, ring-like structures in the disk and correlations between different components of the stellar velocity.
• These perturbations can also cause 'phase wrapping' signatures in the disk, such as arched velocity structures in the motions of stars in the Galactic plane.