First detection of CHD₂OH towards pre-stellar cores

The inheritance of material across the star and planet formation process is traced by deuterium fractionation. We report here first detection doubly deuterated methanol towards pre-stellar cores. study fractionation methanol, CH$_{3}$OH, two starless derive a D/H ratio 0.8-1.9$\%$ with CH$_{2}$DOH in cores H-MM1 L694-2, consistent measurements more evolved Class 0/I objects comet 67P/Churyumov-Gerasimenko, suggesting direct chemical link arising stage. Furthermore, column density ratios CHD$_{2}$OH/CH$_{2}$DOH are $\sim$50-80$\%$, consistently high as that objects, indicating an efficient mechanism CHD$_{2}$OH, possibly through H atom additions to D$_{2}$CO. CH$_{2}$DOH/CH$_{3}$OH CHD$_{2}$OH/CH$_{3}$OH larger than B68 L1521E, representing evolutionary trend deuteration early-stage