SiO maser emission from OH/IR stars and a search for Orion-like SiO masers.

Six new detections of v = 1, J = 1-O SiO masers from OH/IR and IRC sources are reported, together with the negative results of a sensitive search for Orion-like SiO masers in galactic star-forming regions. A high detection rate of SiO masers in OH/IR stars was found, suggesting that the SiO maser phenomenon may be widespread in these objects. The failure to detect SiO masers in any star-forming region but Orion-KL indicates that the Orion SiO maser source is a very unusual object.