抄録
Abstract
Methanol is one of the most abundant complex organic molecules in interstellar environments. Molecular lines of its rare isotopologues 12CH3 17OH and 12CH3 18OH therefore play a crucial role in examining the column density of 12CH3 16OH, which serves as a reference for organic molecular chemistry in interstellar clouds. In this study, we have recorded the spectroscopic emission spectrum of 12CH3 17OH in the frequency range between 216 and 264 GHz by making use of an emission-type millimeter and submillimeter spectrometer. We have specifically paid attention to the Q-branch transitions, which are the strongest line series in this frequency region. Among the stable oxygen isotopes, 16O, 17O, and 18O of methanol, only 12CH3 17OH obviously shows line profiles having double and/or triple peaks in low-J transitions, due to the nuclear quadrupole interaction. The newly obtained 12CH3 17OH data will play an important role in facilitating a deeper understanding of the organic chemistry related to star and planet formation. The 12CH3 17OH line data allow us to trace and constrain the isotopic ratio 17O/18O in methanol, which is efficient to investigate the galactic-scale evolution of elements. In addition, we also assigned some transitions of 13CH3 17OH in the recorded spectrum.