Local stellar kinematics from RAVE data: II. Radial Metallicity Gradient

TL;DR

This study analyzes the radial metallicity gradient in the Milky Way's disc using RAVE data, revealing that younger stars exhibit steeper gradients than older stars, with implications for galactic chemical evolution.

Contribution

It provides the first detailed measurement of the radial metallicity gradient for different stellar populations using RAVE DR3 data, employing probabilistic and dynamical classifications.

Findings

Younger thin disc stars have a metallicity gradient of -0.051 dex/kpc.

Older thin disc stars show shallower metallicity gradients.

The gradient varies with stellar age and orbital eccentricity.

Abstract

We investigate radial metallicity gradients for a sample of dwarf stars from the RAdial Velocity Experiment (RAVE) Data Release 3 (DR3). We select a total of approximately 17000 F-type and G-type dwarfs using selection of colour, log g, and uncertainty on derived space motion, calculate for each star a probabilistic (kinematic) population assignment to thick or thin disc using space motion, and additionally another (dynamical) assignment using stellar vertical orbital eccentricity. We additionally subsample by colour, to provide samples biased to young thin disc and to older thin disc stars. We derive a metallicity gradient as a function of Galactocentric radial distance, i.e. d[M/H]/dR_m=-0.051+/-0.005 dex kpc^-1, for the youngest sample, F-type stars with vertical orbital eccentricities e_V<=0.04. Samples biased to older thin disc stars show systematically shallower abundance gradients.