We present the first high spatial and spectral observations of the circumstellar envelope ( CSE ) of a B [ e ] supergiant ( CPD -57 \mathrm { { } ^ { \circ } } 2874 ) , performed with the Very Large Telescope Interferometer ( VLTI ) .
Spectra , visibilities , and closure phase , were obtained using the beam-combiner instruments AMBER ( near-IR interferometry with three 8.3Â m Unit Telescopes or UTs ) and MIDI ( mid-IR interferometry with two UTs ) .
The interferometric observations of the CSE are well fitted by an elliptical Gaussian model with FWHM diameters varying linearly with wavelength .
Typical diameters measured are \simeq 1.8 \times 3.4 Â mas or \simeq 4.5 \times 8.5 Â AU ( adopting a distance of 2.5 Â kpc ) at 2.2 \mu \mathrm { m } , and \simeq 12 \times 15 Â mas or \simeq 30 \times 38 Â AU at 12 \mu \mathrm { m } .
The size of the region emitting the Br \gamma flux is \simeq 2.8 \times 5.2 Â mas or \simeq 7.0 \times 13.0 Â AU .
The major-axis position angle of the elongated CSE in the mid-IR ( \simeq 144 \mathrm { { } ^ { \circ } } ) agrees well with previous polarimetric data , hinting that the hot-dust emission originates in a disk-like structure .
In addition to the interferometric observations we also present new optical ( UBVR _ { c } I _ { c } ) and near-IR ( JHKL ) broadband photometric observations of CPD -57 \mathrm { { } ^ { \circ } } 2874 .
Our spectro-interferometric VLTI observations and data analysis support the non-spherical CSE paradigm for B [ e ] supergiants .