Mono-deuterated methanol is thought to form during the prestellar core stage of star formation. Observed variations in the CH2DOH/CH3OD ratio suggest that its formation is strongly dependent on the surrounding cloud conditions. Thus, it is a potential tracer of the physical conditions before the onset of star formation. A single-point physical model representative of a typical prestellar core is coupled to chemical models to investigate potential formation pathways towards deuterated methanol at the prestellar stage. Simple addition reactions of H and D are not able to reproduce observed abundances. The implementation of an experimentally verified abstraction scheme leads to the efficient formation of methyl-deuterated methanol, but lacks sufficient formation of hydroxy-deuterated methanol. CH3OD is most likely formed at a later evolutionarymstage, potentially from H-D exchange reactions in warm ices between HDO (and D2O) and CH3OH. The CH2DOH/CH3OD ratio is not an appropriate tracer of the physical conditions during the prestellar stage, but might be better suited as a tracer of ice heating.
@article{arxiv.2204.01035,
title = {Fevering Interstellar Ices Have More CH3OD},
author = {Beatrice M. Kulterer and Maria N. Drozdovskaya and Stefano Antonellini and Catherine Walsh and Tom J. Millar},
journal= {arXiv preprint arXiv:2204.01035},
year = {2022}
}
Comments
Accepted for publication in ACS Earth and Space Chemistry; 56 pages, 7 figures