We report various recent observations of molecules in circumstellar envelopes of late type stars, mainly possible proto-planetary nebulae at various stages of evolution, and supergiants, including.
First observation of SO2 (Lucas et al. 1986) in five stars and SO in one. S O 2 is particularly strong in OH 231.8+4.2 (OH 0739-14) and OH 26.5+0.6, where one of its lines is the strongest non-maser line observed in these envelopes (Guilloteau et al. 1986).