Introduction

A method of detecting new planetary nebulae (PN) based on their infrared colours from the IRAS Point Source Catalogue is described by Pottasch et al. (1988). This method has been used in several subsequent investigations, for example those by Van de Steene & Pottasch (1993) and Van de Steene, Sahu, & Pottasch (1996). The method is based on the fact that the vast majority of PN fall within the colour box bounded by F12/F25 0.35 and F25/F60 0.35, where F12, F25, and F60 refer to the fluxes in the IRAS wavelength bands centred at 12, 25, and 60 m respectively.

In this investigation, sources were chosen from inside this colour box that were also present in the Parkes-MIT-NRAO (PMN) 5 GHz Catalogue of Point Sources. A list of 206 sources was compiled in this way, and it was found that 115 corresponded to known PN. A shortlist of 75 candidate fields was compiled, containing no known PN and no obvious correspondence with other known objects (typically HII regions, SNR).

© Copyright Astronomical Society of Australia 1997