A high spatial resolution view of the silicates in young eruptive stars

The unpredictable eruptions of FU Ori- and EX Lup-type young pre-main sequence stars are expected to have a strong impact on the surrounding circumstellar material, and thus on the initial conditions of planet formation. The episodically increased luminosity of the central object may drive structural, chemical and mineralogical changes in the inner disk. Here we present a study of the silicate component in a sample of 11 young eruptive stars. We use archival mid-infrared interferometric observations obtained with the MIDI instrument on the VLTI. We compare the observed emission/absorption profiles of the 10 micrometer silicate feature with spectral templates of amorphous dust and comet Hale-Bopp. The interferometric data allow us to perform the analysis on different spatial scales between 1-2 au and 20-30 au. In particular, we aim to reveal the expected existence of crystalline silicates in the environment of the high luminosity FU Orionis objects, which has never been observed so far. Our results provide the first high resolution view of the silicate particles in young eruptive stars, and help to outline those astrophysical situations when mineralogical changes occur in space.