Description
Carbon is one of the most abundant components in the Universe. While silicates have been the main focus of solid phase studies in ProtoPlanetary Discs (PPDs), little is known about the solid carbon content especially in the planet-forming regions ( ~0.1 to 10 au). Fortunately, several refractory carbonaceous species present C-H bonds (like hydrogenated nano-diamond and amorphous carbon, Polycyclic Aromatic Hydrocarbons (PAHs)), which generate IR features that can be used to trace the solid carbon reservoirs. The new mid-infrared instrument MATISSE, installed at the Very Large Telescope Interferometer, can spatially resolve the inner regions (~1 to 10~au) of PPDs and locate, down to the au-scale, the emission coming from carbon grains. We present the first MATISSE L-band observations of the Herbig Ae star HD179218. Its disk exhibits an unusual extended inner emission up to 10 au, which could be due to carbonaceous species. We simultaneously modeled the SED and all the available interferometric data to provide a global view on the spatial structure of the inner disk region and give preliminary constraints on the location of the carbonaceous grain emitting region. Finally, in the perspective of upcoming MATISSE observations at higher spectral resolution we assess the feasibility of detailed characterization of the carbonaceous grain emission in the 1-10 au region.
