  The Milky Way has distinct structural stellar components linked to its
formation and subsequent evolution, but disentangling them is nontrivial. With
the recent availability of high-quality data for a large numbers of stars in
the Milky Way, it is a natural next step for research in the evolution of the
Galaxy to perform automated explorations with unsupervised methods of the
structures hidden in the combination of large-scale spectroscopic, astrometric,
and asteroseismic data sets. We determine precise stellar properties for 21,076
red giants, mainly spanning 2-15 kpc in Galactocentric radii, making it the
largest sample of red giants with measured asteroseismic ages available to
date. We explore the nature of different stellar structures in the Galactic
disc by using Gaussian mixture models as an unsupervised clustering method to
find substructure in the combined chemical, kinematic, and age subspace. The
best-fit mixture model yields four distinct physical Galactic components in the
stellar disc: the thin disc, the kinematically heated thin disc, the thick
disc, and the stellar halo. We find hints of an age asymmetry between the
Northern and Southern hemisphere and we measure the vertical and radial age
gradient of the Galactic disc using the asteroseismic ages extended to further
distances than previous studies.
