Abstract
The recently defined Galactic FS CMa group comprises ∼ 40 not very luminous objects that significantly expand the luminosity range of hot dust-forming stars. These objects exhibit extremely strong emission-line spectra and IR excesses, which are indicative of compact dust envelopes. They are most likely binary systems that currently undergo or have recently undergone a phase of a rapid mass exchange, associated with dust formation. Complex structure of the circumstellar environments significantly veils the underlying stars and requires multitechnique investigation, in which interferometry should play an important role.
