Identification of Methyl Isocyanate and Other Complex Organic Molecules in a Hot Molecular Core, G31.41+0.31

Abstract

G31.41+0.31 is a well known chemically rich hot molecular core (HMC). Using Band 3 observations from the Atacama Large Millimeter Array (ALMA), we have analyzed the chemical and physical properties of the source. We have identified methyl isocyanate (CH3NCO), a precursor of prebiotic molecules, toward the source. In addition to this, we have reported the presence of complex organic molecules (COMs) like methanol (CH3OH), methanethiol (CH3SH), and methyl formate (CH3OCHO). Additionally, we have used transitions from molecules like HCN, (HCO+)-C-13, and SiO to trace the presence of infall and outflow signatures around the star-forming region. For the COMs, we have estimated the column densities and kinetic temperatures, assuming molecular excitation under local thermodynamic equilibrium (LTE) conditions. From the estimated kinetic temperatures of certain COMs, we found that multiple temperature components may be present in the HMC environment. Comparing the obtained molecular column densities between the existing observational results around other HMCs, it seems that the COMs are favorably produced in the hot core environment (similar to 100 K or higher). Though the spectral emissions toward G31.41+0.31 are not fully resolved, we find that CH3NCO and other COMs are possibly formed on grain/ice phase and populate the gas environment similar to other hot cores like Sgr B2, Orion KL, and G10.47+0.03.