The disappearance of the 1667-MHz OH maser in IRAS 17436+5003 (HD 161796)

We report the diminution of the 1667-MHz OH maser in the post-asymptotic giant branch star IRAS 17436+5003, by a factor of ≳17 over a period of ≲12 yr, from observations with MERLIN. This circumstellar maser was detected by Likkel in 1987, at the 13σ level of her observations with the Green Bank Telescope. We discuss a number of possible reasons for this phenomenon and conclude that it is most likely due to turbulence arising from interacting stellar winds.