Cepheids as Swiss army knives for Milky Way archaeology

Cepheids are excellent stellar tracers: they are bright enough to be observed even at large distances; their distances can be accurately determined via period-luminosity relations; their spectra contain numerous lines that enable us to derive abundances for many α, iron-peak or neutron-capture elements. Classical Cepheids are yellow supergiants that trace the young populations (<= 300 Myr) Type II Cepheids are post Horizontal Branch, low-mass, Population II stars (>= 10 Gyr). Both can be used for many purposes in Milky Way archaeology.