Interstellar extinction of classical Cepheids from neighboring stars. I. Methodology and application to 16 Galactic Cepheids
Galactic Cepheid variable stars are fundamental calibrators of the cosmic distance scale through their period-luminosity (PL) relation. The high-precision parallaxes expected from Gaia Data Release 4 (DR4) will enable a calibration of the Milky Way PL relation with unprecedented precision. This will place stringent req...