Constraints on the history of Galactic spiral arms revealed by Gaia GSP-Spec alpha-elements
M. Barbillon, A. Recio-Blanco, E. Poggio, P. A. Palicio, E. Spitoni,, P. de Laverny, G. Cescutti

TL;DR
This study uses Gaia DR3 data to map azimuthal chemical variations in the Milky Way's disc, revealing how spiral arms influence elemental abundances and advancing our understanding of galactic chemical evolution.
Contribution
It introduces a 2D chemical mapping approach using alpha-elements, linking chemical inhomogeneities to spiral arm structures and dynamics.
Findings
Young stars in spiral arms are more metal-rich and have lower [alpha/Fe] ratios.
Azimuthal [alpha/Fe] fluctuations correlate with spiral arm locations.
Old star maps show chemical deficiencies along the Local arm segment.
Abstract
The distribution of chemical elements in the Galactic disc can reveal fundamental clues on the physical processes that led to the current configuration of our Galaxy. We map chemical azimuthal variations in the disc using individual stellar chemical abundances and discuss their possible connection with the spiral arms and other perturbing mechanisms. Using Gaia Data Release 3, we examine [Ca/Fe] and [Mg/Fe] fluctuations in a ~4 kpc region around the Sun, focusing on bright giant stars. We implemented a kernel density estimator technique to enhance the chemical inhomogeneities. We observe radial gradients and azimuthal fluctuations in [alpha/Fe] for young (<150 Myr) and old (>2 Gyr) stars, with amplitudes varying according to the studied element. In young stars, those within spiral arms (e.g., Sagittarius-Carina and Local arms) are generally more metal and calcium-rich (~0-0.19 dex) but…
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Taxonomy
TopicsAstronomy and Astrophysical Research · Geomagnetism and Paleomagnetism Studies · Astro and Planetary Science
