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Diane-Feuillet

Diane Feuillet

Researcher

Diane-Feuillet

Spatial variations in the Milky Way disc metallicity-age relation

Author

  • Diane Feuillet
  • Neige Frankel
  • Karin Lind
  • Peter Frinchaboy
  • D A Garcia-Hernandez
  • Richard Lane
  • Christian Nitschem
  • Alexandre Roman-Lopes

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