# VISIR imaging of VY CMa

Coordinator: Ralf Siebenmorgen and Endrik Kruegel

Supergiants are, besides AGB stars and supernovae, the major suppliers of dust to the interstellar medium. Furthermore, they are extremely luminous and in a pre-supernova stage of evolution. Among them, VY CMa is one of the most spectacular representatives. We wish to map VY CMa in the Q-band. From previous TIMMI observations on the 3.6m (Smith et al., 2001, AJ 121, 1111), we expect the circumstellar shell to have an extension slighly greater than 10$"$, its emission should be optically thin ($A_{\rm V \simeq 15$mag). Through imaging the object, we will delineate the density distribution of the circumstellar dust, also with respect to the star, and by interpreting the data in the framework of a 2d radtiative transfer, derive the temperature profile. Another interesting problem that can be tackled with the 0.6$"$ spatial resolution attainable on the VLT at 20$\mu$m concerns the apparent disk-like structure seen in the 10$\mu$m image. A disk (or torus) is usually the result of rotation, but for a star as big as Jupiter, rotation must be unimportant. The new 20$\mu$m image can help to seek an alternative explanation (binary system?).