Survey of CH<sub>3</sub>NH<sub>2</sub> and its Formation Process
T. Suzuki, Liton Majumdar, P. F. Goldsmith, Kazuki Tokuda, Harumi Minamoto, Masatoshi Ohishi, Masao Saito, Tomoya Hirota, Hideko Nomura, Yoko Oya
Abstract
Abstract We present the observational results of a precursor of glycine, methylamine (CH 3 NH 2 ), together with methanol (CH 3 OH) and methanimine (CH 2 NH) for the high-mass star-forming regions NGC 6334I, G10.47+0.03, G31.41+0.3, and W51 e1/e2 using the Atacama Large Millimeter/submillimeter Array. The molecular abundances of these sources were derived using the CASSIS spectrum analyzer and compared with our state-of-the-art three-phase chemical model NAUTILUS . We found that the observed abundance ratio of CH 3 NH 2 /CH 3 OH is between 0.008 and 1.0 for all sources, except for NGC 6334I MM3, where a ratio less than 0.002 is found. This may be due to its later evolutionary stage relative to the other cores. We also found that the observed CH 3 NH 2 /CH 3 OH ratio agrees well with the three-phase chemical model NAUTILUS , which includes the formation of CH 3 NH 2 on the grain surface via a series of hydrogenation processes of HCN. This result clearly shows the importance of hydrogenation processes to form CH 3 NH 2 .