Astronomy departmental seminar - Diane Feuillet


Characterizing epochs of star formation across the Milky Way disc using age-metallicity distributions of GALAH stars


The age-metallicity relation of a galaxy is predicted to reflect its star formation history, providing significant insight into the galaxy’s evolution. However, the observed age-metallicity relation of the Milky Way disk has historically been confusingly featureless, showing little correlation between the age and metallicity of stars. Recently, larger datasets and new statistical analysis methods have revealed significant detail and complexity in the age-metallicity relation of the Milky Way disk. We present a detailed map of the ages and metallicities of turn-off stars in the Milky Way disk based on data from GALAH DR3 and Gaia EDR3. From this map, we identify previously undetected features in the age-metallicity distribution of disc stars and interpret these results as indicating a three-phase formation history of the Milky Way.