THE STRUCTURE OF THE NARROW EMISSION BANDS NEAR 10-MU-M

High quality spectra at 8-13-mu-m of five compact objects that display narrow infrared emission bands are presented. All of the objects display the well-known 11.25- and 8.56-mu-m features together with the long wavelength wing of the 7.7-mu-m band. In addition, weaker bands near 11.05 and 11.5-mu-m and/or 'plateau' emission between the 11.25- and 12.7-mu-m features are evident in some of the objects. There is considerable dispersion as to the equivalent width of the features from object to object. The pre-main sequence star TY CrA has a remarkable spectrum, displaying an especially pronounced feature at 11.05-mu-m, with an intensity 25 per cent that of the 11.25-mu-m feature, and a very prominent 8.6-mu-m band. Overall, the structure apparent in the 11-13-mu-m region is reflected in the prominence of the 8.6-mu-m feature and the complexity in the emission features near 3-mu-m. The observations are discussed in terms of emission from polycyclic aromatic hydrocarbons.