We present observations of six transitions of CH2DOH towards the Orion-IRc2 molecular cloud. We believe that we have clearly detected five of these and estimate on this basis that the CH2DOH column density is 3.4(-O.8, +2) 1O15 cm-2. We also present new observations of CH3OD and use these new data together with older results to conclude that the abundance ratio [CH2DOH] / [CH3OD] is in the range 1.1-1.5. On the basis of a new map of the 51- - 50+ A transition of CH3OD, we conclude that deuterated methanol is most abundant in the region about 6 arc seconds to the south of the Orion hot core which is sometimes referred to as the compact ridge. Additionally, we use our new data in order to estimate the abundance ratio for A to E-type CH3OD and we find a value of 1.2 (±0.3). The consequences of these new results for models of methanol formation in the Orion region are briefly discussed.
Astronomy and Astrophysics
- Pub Date:
- April 1993
- grain mantle;
- interstellar medium: clouds: Orion