Characterisation of the Galactic thin disc with Corot targets

TL;DR

This study characterizes the Milky Way's thin disc using Corot star data, revealing metallicity gradients, kinematic properties, and evidence for radial migration, with implications for understanding Galactic structure and evolution.

Contribution

It provides a detailed kinematic and chemical analysis of Corot stars in the Galactic thin disc, including metallicity gradients and migration evidence, using combined observational data and models.

Findings

Radial metallicity gradient of -0.097 dex/kpc with giants.

Significant correlation between V-velocity and metallicity at 2-sigma.

Planet-hosting stars mainly belong to the thin disc with normal properties.

Abstract

We use kinematical and chemical properties of 754 Corot stars to characterise the stellar populations of the Milky Way disc in three beams close the Galactic plane. From the atmospheric parameters derived in Gazzano et al. (2010) with the Matisse algorithm, we derived stellar distances using isochrones. Combining these data with proper motions, we provide the complete kinematical description of stars in three Corot fields. Finally, we used kinematical criteria to identify the Galactic populations in our sample and study their characteristics, particularly their chemistry. Comparing our kinematics with the Besancon Galactic model, we show that, within 3-sigma, simulated and observed kinematical distributions are in good agreement. We study the characteristics of the thin disc, finding a correlation that is significant at a value of 2-sigma between the V-velocity component and the metallicity for two different radial distance bins (8-9kpc and 9-10kpc; but not for the most inner bin 7-8kpc, probably because of the uncertainties in the abundances) which could be interpreted as radial migration evidence. We also measured a radial metallicity gradient value of -0.097+/-0.015dex/kpc with giant stars, and -0.053+/-0.015dex/kpc with dwarfs. Finally, we identified metal-rich stars with peculiar high [alpha/Fe] values in the directions pointing to the inner part of the Galaxy. Applying the same methodology to the planet-hosting stars detected by Corot shows that they mainly belong to the thin disc population with normal chemical and kinematical properties.