Crété E. , Giard M. , & Joblin C.
Centre d'Étude Spatiale des Rayonnements, 9, avenue du Colonel Roche, BP 4346, F-31028 Toulouse Cedex 04, France
We will present high angular resolution Isocam observations
(1.5 arcsecond per pixel) of the M17 HII region/molecular cloud
interface from 4.5 to 10 
m.
These allowed us to map the 6.2 m and 7.7 m carbonaceous
dust features together with the adjacent continuum.
Analyzed with ground-based data at 3.3 m,
these data are compared with the PAH and Coal dust models.
We show that the observations favor the models with
nano-metric sized particles, even in the direction of the HII
region. In addition to the classical PAH component which
is located at the HII/molecular interface and is responsible
for the classical emission features, our data show the presence of an
additional component of nanometric
particles emitting in the 8 to 10 m range in the direction
of the HII region.