고 은위 분자운 MBM12 중심에서의 성간 분자들의 함량

MOLECULAR ABUNDANCES IN THE CORE OF THE HIGH-LATITUDE CLOUD MBM12

We observed the molecular transitions of $^{12}CO(1-0)$, $^{13}CO(1-0)$, $C^{18}O(1-0)$, CS(2-1), $HCO^+(1-0)$, and HCN(1-0) toward the high-latitude mole cular cloud MBM12. We derived total $H_2$ column densities for the two velocity components using the optically thin $C^{18}O$ transition. Molecular abundances have been derived for the observed species at the core of this cloud, which appear to be less than an order of magnitude in fractional abundances relative to $H_2$, compared to typical cold dark clouds.