1994A&A...292..593P

We have observed 7 young intermediate mass stars in the mid-infrared with two diaphragms of different sizes in order to detect extended emission. The mid-infrared part of the spectral energy distribution of HD97048, HD97300, and HD176386 is dominated by extended emission. The extended mid-infrared emission can best be explained with emission from large molecules and small grains in a dust shell with a large inner cavity devoid of small particles. The 4 strong mid-infrared sources of our sample (T CrA, R CrA, HD104237 and IRAS12496-7650) are dominated by emission within the smallest diaphragm (5.4") used in this work. When extended emission around Herbig Ae/Be stars is present, it contributes significantly to the mid-infrared luminosity and must be taken into account both in future observational and theoretical studies.