An OH mainline maser survey of IRAS circumstellar envelope sources.

We present the results of a survey in the OH mainline at 1667 MHz. Because this line is generally weak in the OH/IR stars, systematic surveys of the mainline maser have not been previously performed, 131 sources were detected out of which 108 were previously unknown. The 1667 MHz profile in OH/IR stars is similar in form to that of the 1612 MHz emission, the relevant maser properties have been measured under the assumption of the habitual radially expanding envelope model for circumstellar envelopes. We show that the mainline maser is still present in circumstellar envelopes with cool [60/25] colours, its detection is, in fact, higher for such colours. Summary detection rates are given. A deeper analysis will be presented in a forthcoming paper