Evolution of the Velocity Ellipsoids in the Thin Disk of the Galaxy and the Radial Migration of Stars

TL;DR

This study investigates how radial migration affects the evolution of stellar velocity ellipsoids in the Galaxy's thin disk, revealing its role in the observed metallicity-angular momentum correlation among nearby stars.

Contribution

It demonstrates that radial migration combined with metallicity gradients explains the negative correlation between metallicity and angular momentum in the thin disk.

Findings

Radial migration influences the age dependence of velocity ellipsoid parameters.

Stars born at the same Galactocentric distance show no dependence of angular momentum on age or metallicity.

Radial migration and metallicity gradients explain the metallicity-angular momentum correlation.

Abstract

Data from the revised Geneva--Copenhagen catalog are used to study the influence of radial migration of stars on the age dependences of parameters of the velocity ellipsoids for nearby stars in the thin disk of the Galaxy, assuming that the mean radii of the stellar orbits remain constant. It is demonstrated that precisely the radial migration of stars, together with the negative metallicity gradient in the thin disk,are responsible for the observed negative correlation between the metallicities and angular momenta of nearby stars, while the angular momenta of stars that were born at the same Galactocentric distances do not depend on either age or metallicity. (abridged)