High-angular resolution observations of HD179218: Early stages of disk dissipation?

Star/disk interactions have an important effect on disk evolution (e.g. photoevaporation). We present an extensive multi wavelength (visible, near- and mid-infrared) high-angular resolution observational campaign involving seven instruments (direct imaging and interferometry), on HD179218, a Herbig star surrounded by a (pre-)transitional disk. Its near-infrared circumstellar emission is ~50 times larger than its theoretical dust sublimation radius making it very special amongst other Herbig stars observed by infrared interferometry. This emission has an unexpectedly high temperature (∼1500 K) that we postulate to explain by small carbon particles super-heated by high energy photons from the central star. This points toward a scenario where the inner disk parts were accreted onto the star and the rest of the disk is being photo-evaporated by high energy stellar photons. It makes this target unique as it would be the first one to be caught in very early stages of disk dissipation.