Spatial variations in the Milky Way disc metallicity-age relation

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift


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.


  • Diane Feuillet
  • Neige Frankel
  • Karin Lind
  • Peter Frinchaboy
  • D A Garcia-Hernandez
  • Richard Lane
  • Christian Nitschem
  • Alexandre Roman-Lopes
Externa organisationer
  • Max Planck Institute for Astronomy
  • Texas Christian University
  • Instituto de Astrofísica de Canarias
  • Pontifical Catholic University of Chile
  • University of Antofagasta
  • Universidad de La Serena


Sidor (från-till)1742-1752
Antal sidor12
TidskriftMonthly Notices of the Royal Astronomical Society
Utgåva nummer2
StatusPublished - 2019 okt
Peer review utfördJa
Externt publiceradJa