Published online by Cambridge University Press: 04 August 2017
We have obtained spectra in the three micron region of a sample of IRAS sources showing a strong 11.3 micron emission feature in their IRAS Low-Resolution Spectra (LRS). The observations have been carried out from ESO (La Silla, Chile) and from UKIRT (Mauna Kea, Hawaii), between March and September 1985. All sources but one turn out to have a more or less strong 3.3 micron emission feature, and additionally in most cases a feature at 3.4 micron, extending into a plateau from 3.45 to 3.60 micron. in one particular case we have resolved the plateau into 3 features at 3.45, 3.51 and 3.56 micron. These are detected for the first time.