A Test for Radial Mixing Using Local Star Samples

Abstract

We use samples of local main-sequence stars to show that the radial gradient of [Fe/H] in the thin disk of the Milky Way decreases with mean effective stellar temperature. Many of these stars are visiting the solar neighborhood from the inner and outer Galaxy. We use the angular momentum of each star about the Galactic center to determine the guiding center radius and to eliminate the effects of epicyclic motion, which would otherwise blur the estimated gradients. We interpret the effective temperature as a proxy for mean age, and conclude that the decreasing gradient is consistent with the predictions of radial mixing due to transient spiral patterns. We find some evidence that the trend of decreasing gradient with increasing mean age breaks to a constant gradient for samples of stars whose main-sequence life-times exceed the likely age of the thin disk.

Accepted to appear in ApJ, 8 pages, 8 figures

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• The Impact of Stellar Migration on Disk Outskirts
• The role of radial migration on tracing lithium evolution in the Galactic disk
• Spatial metallicity variations of mono-temperature stellar populations revealed by early-type stars in LAMOST
• Tracking Cluster Debris (TraCD)- I. Dissolution of clusters and searching the solar cradle
• Revisiting the Radial Metallicity Gradient-Age Relation in the Milky Way's Thin and Thick Disks