1996A&A...312..511H

We report on the results of a search for an emission feature at 21µm from the IRAS data base. Using the sophisticated IRAS-GIPSY software, we are able to obtain and to select reliable LRS spectra from the IRAS data base. Twelve out of more than 900 sources from the IRAS Point Source Catalogue, whose flux at 12µm is larger than 5Jy were selected as new candidates with a 21-µm feature (5 objects are firmly identified, 7 are on a ``waiting list''). These objects belong both to the class of proto-planetary nebulae and to the class of young stellar objects. It is possible that the appropriate circumstellar environment for objects with a 21-µm feature exists in two different stages of stellar evolution which points to the basic nature of the physical and chemical processes involved.