Corotation, Stellar Wandering, and Fine Structure of the Galactic Abundance Pattern

Abstract

We consider the effects of the corotation resonance of the Galactic spiral structure on the stellar orbits. It is shown that because of resonant interaction with the spiral gravitation field, stars can wander in the radial direction over a large part of the Galactic disk, moving over distances ~2-3 kpc in a short time, on the order of 1 billion years or even much less. This mechanism of radial stellar wandering is much faster than other stellar diffusion mechanisms that have been suggested in the literature. Corotation resonance also influences the Galactic distribution of heavy elements that are derived from old stellar-like objects. If at the initial time there is a simple linear distribution of metallicity in the disk, this is broken in ~3 billion years. In the framework of the model for the spiral density wave pattern with the corotation resonance close to the solar position (supposed to be 8.5 kpc from the center), the bimodal abundance pattern with a gradient in the inner part of the Galaxy (R