Stellar multiplicity aspect in the chemo-dynamic Milky Way disk model

The Just-Jahreiß (JJ) model describes an axisymmetric Milky Way (MW) disk and is a tool for stellar population synthesis. It includes exponential thin and thick disks, atomic and molecular gas layers, spherical stellar halo, and cored isothermal dark matter sphere. The overall thin-disk thickness is independent of radius, and the radial variation of the thin-disk SFR reflects the inside-out disk growth. A smooth power-law star formation rate (SFR) continuum can be modified by an arbitrary number of Gaussian peaks consisting of dynamically hot stars, thus, representing gas infall episodes. For the stellar population synthesis, the JJ model is complemented by three alternative isochrone sets – PARSEC, MIST, and BaSTI.
Up to now, the JJ model relies only on single-star evolution models, but the lack of binaries reveals itself when the modeled and realistic observed color-magnitude diagrams (CMD) are compared. As CMD comparison is often used to optimize the model parameters, it is necessary to account for binary stellar evolution in the future.