Abstract
We report here on the detection of CO(J = 1 --> 0), and (J = 2 --> 1) emission towards two distant OH/IR stars, OH0.3-0.2 and OH18.5 + 1.4. From the CO(J = 1 --> 0) emission the estimated mass loss rates are 1.2 x 10(-5) and 1.6 x 10(-5) M. yr-1, respectively. These mass loss rates are lower by a factor of almost-equal-to 2 compared to those estimated from the OH 1612 MHz maser emission. The detected sources belong to a small group of OH/IR stars without significant variability in the OH 1612 MHz maser emission. It has been suggested that such objects are in the transition phase between highly evolved Asymptotic Giant Branch stars and planetary nebulae. IR observations of both objects support this suggestion. OH0.3-0.2, which is probably located, in the central region of the Galaxy, has a radial velocity of -341 km s-1 with respect to the Local Standard of Rest, placing it at the upper end of high velocity objects in the Galaxy.