Long baseline interferometry, a powerful tool to study stars with the B[e] phenomenon: The case of HD50138

HD50138 is one the closest star with the B[e] phenomenon. However, up to now its evolutionary stage is not well known. 
Thanks to optical high-resolution data from the FEROS spectrograph (ESO, La Silla), it was possible to derive the physical 
parameters of this star (B6-7 III-V) and its circum- and interstellar extinction. This object can represent a link between Be and 
B[e] stars, and based on its intense spectral variation, we tentatively suggest that a new shell phase could have taken place 
prior to our observations in 2007. From the high spatial resolution provided by AMBER and MIDI (VLTI/ESO), we identified the 
presence of a gaseous and dusty circumstellar disk. In addition, we could also derive the structure, inclination related to line 
of sight, and orientation onto the sky-plane of the circumstellar disk of HD50138.