Oral Presentation

Revealing the Chemical Link among NH2CHO, HNCO, and H2CO using ALMA Observations toward High-Mass Protostellar Cores

Author(s): Kotomi Taniguchi (NAOJ), Patricio Sanhueza (NAOJ), Fernando A. Olguin (NTHU), Prasanta Gorai (Chalmers Univ. of Tech.), Ankan Das (Institute of Astronomy Space and Earth), Fumitaka Nakamura (NAOJ), Masao Saito (NAOJ)

Presenter: Kotomi Taniguchi (NAOJ)

Formamide (NH2CHO) is considered to be one of the potential prebiotic molecules because it contains a peptide bond that is important to connect amino acids to form proteins. Although its presence in star-forming regions has been known for around 50 years, its formation process is still controversial. Key points to investigate the formation of molecules are correlation tests including possible precursors. We have analyzed molecular transitions of NH2CHO HNCO, H2CO and CH3CN at ~220 GHz toward 30 high-mass star-forming regions obtained as part of the Digging into the Interior of hot Cores with ALMA (DIHCA) project. We identified 45 hot molecular cores traced by CH3CN in the targeted regions at ~1000 au resolution, and conducted statistical analyses to investigate the chemical link among these four molecules. We found strong positive correlations between NH2CHO and HNCO, and between NH2CHO and H2CO. Our chemical simulations, including the dual-cyclic hydrogen addition and abstraction reactions between NH2CHO and HNCO, and the gas-phase formation of NH2CHO from H2CO, successfully explain the measured observational abundances.