Astronomy & Astrophysics manuscript no. main c ESO 2018 September 25, 2018 Mid-infrared interferometric variability of DG Tau: implications for the inner-disk structure⋆ J. Varga1, K. É. Gabányi1, P. Ábrahám1, L. Chen1, Á. Kóspál1, 4, J. Menu2, Th. Ratzka3, R. van Boekel4, C. P. Dullemond5, Th. Henning4, W. Jaffe6, A. Juhász7, A. Moór1, L. Mosoni1, 8, and N. Sipos1 1 Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, P.O. Box 67, H-1525 Budapest, Hungary e-mail:
[email protected] 2 Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium 3 Institute for Physics/IGAM, NAWI Graz, University of Graz, Universitätsplatz 5/II, 8010, Graz, Austria 4 Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany 5 Institute for Theoretical Astrophysics, Heidelberg University, Albert-Ueberle-Strasse 2, D-69120 Heidelberg, Germany 6 Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands 7 Institute of Astronomy, Madingley Road, Cambridge CB3 OHA, UK 8 Park of Stars in Zselic, 064/2 hrsz., H-7477 Zselickisfalud, Hungary Received; accepted ABSTRACT Context. DG Tau is a low-mass pre-main sequence star, whose strongly accreting protoplanetary disk exhibits a so-far enigmatic be- havior: its mid-infrared thermal emission is strongly time-variable, even turning the 10 µm silicate feature from emission to absorption temporarily. Aims. We look for the reason for the spectral variability at high spatial resolution and at multiple epochs. Methods. Infrared interferometry can spatially resolve the thermal emission of the circumstellar disk, also giving information about dust processing.