Aims. We study the enigmatic B[e] star MWC 300 to investigate its disk and
binary with milli-arcsecond-scale angular resolution. Methods. We observed MWC
300 with the VLTI/AMBER instrument in the H and K bands and compared these
observations with temperature-gradient models to derive model parameters.
Results. The measured low visibility values, wavelength dependence of the
visibilities, and wavelength dependence of the closure phase directly suggest
that MWC 300 consists of a resolved disk and a close binary. We present a model
consisting of a binary and a temperature-gradient disk that is able to
reproduce the visibilities, closure phases, and spectral energy distribution.
This model allows us to constrain the projected binary separation (~4.4 mas or
~7.9 AU), the flux ratio of the binary components (~2.2), the disk temperature
power-law index, and other parameters.Comment: 4 pages, 1 figure, accepted by A&