Radial Metallicity Gradients for the Chemically Selected Galactic Thin Disc Main-Sequence Stars

TL;DR

This study measures the radial metallicity gradients in the Galactic thin disc using chemically selected main-sequence stars, finding minimal impact from orbital variations and contributing to understanding the Galaxy's chemical evolution.

Contribution

It provides new measurements of metallicity gradients for thin-disc stars using chemical selection and Gaia data, accounting for orbital effects and their minimal influence.

Findings

Radial metallicity gradients are approximately -0.074 dex/kpc.

Radial orbital variations have at most a 6% effect on gradient measurements.

Gradients persist across stellar ages with minimal orbital variation impact.

Abstract

{We present the radial metallicity gradients within the Galactic thin disc population through main-sequence stars selected on the chemical plane using GALAH DR3 accompanied with Gaia DR3 astrometric data. The [Fe/H], [$\alpha$/Fe] and [Mg/H] radial gradients are estimated for guiding radius as $-0.074\pm 0.006$, $+0.004\pm0.002$, $-0.074\pm0.006$ dex kpc$^{-1}$ and for the traceback early orbital radius as $-0.040\pm0.002$, $+0.003\pm 0.001$, $-0.039\pm 0.002$ dex kpc$^{-1}$ for 66,545 thin-disc stars, respectively. Alteration of the chemical structure within the Galactic disc caused by the radial orbital variations complicates results for the radial metallicity gradient. The effect of radial orbital variations on the metallicity gradients as a function on time indicates the following results: (i) The presence of a gradient along the disc throughout the time for which the model provides similar prediction, (ii) the radial orbital variations becomes more pronounced with the age of the stellar population and (iii) the effect of radial orbital variations on the metallicity gradients is minimal. The effect of radial orbital variations is found to be at most 6\% which does not statistically affect the radial gradient results. These findings contribute to a better understanding of the chemical evolution within the Galactic disc and provide an important basis for further research.