Diane Feuillet
Researcher
Spatial variations in the Milky Way disc metallicity-age relation
Author
Summary, in English
Stellar ages are a crucial component to studying the evolution of the Milky Way. Using Gaia DR2 distance estimates, it is now possible to estimate stellar ages for a larger volume of evolved stars through isochrone matching. This work presents [M/H]-age and [α/M]-age relations derived for different spatial locations in the Milky Way disc. These relations are derived by hierarchically modelling the star formation history of stars within a given chemical abundance bin. For the first time, we directly observe that significant variation is apparent in the [M/H]-age relation as a function of both Galactocentric radius and distance from the disc mid-plane. The [M/H]-age relations support claims that radial migration has a significant effect in the plane of the disc. Using the [M/H] bin with the youngest mean age at each radial zone in the plane of the disc, the present-day metallicity gradient is measured to be -0.059 ± 0.010 dex/kpc, in agreement with Cepheids and young field stars. We find a vertically flared distribution of young stars in the outer disc, confirming predictions of models and previous observations. The mean age of the [M/H]-[α/M] distribution of the solar neighbourhood suggests that the high-[M/H] stars are not an evolutionary extension of the low-α sequence. Our observational results are important constraints to Galactic simulations and models of chemical evolution.
Publishing year
2019-10
Language
English
Pages
1742-1752
Publication/Series
Monthly Notices of the Royal Astronomical Society
Volume
489
Issue
2
Document type
Journal article
Publisher
Oxford University Press
Topic
- Astronomy, Astrophysics and Cosmology
Keywords
- Galaxy: abundances
- Galaxy: disc
- Galaxy: evolution
- Galaxy: stellar content
- Astrophysics - Astrophysics of Galaxies
- Astrophysics - Solar and Stellar Astrophysics
Status
Published
ISBN/ISSN/Other
- ISSN: 1365-2966