Cool evolved stars as seen by the Very Large Telescope Interferometer: Power of infrared spectro-interferometry

Two interferometric instruments at ESO's Very Large Telescope Interferometer (VLTI), MIDI and AMBER which operate in the mid‐infrared (8–13 μm) and the near‐infrared (JHK) respectively, have proven to be powerful tools to probe the circumstellar environment of evolved stars. Their spectro‐interferometric capability enables us to observe objects with spectral and spatial information disentangled. VLTI observations confirm our pictures on the circumstellar environment of cool evolved stars in some cases but bring about entirely unexpected pictures for other cases. Here, we present particularly our recent results obtained with VLTI/MIDI.