Study of Complex Nitrogen and Oxygen-bearing Molecules toward the High-mass Protostar IRAS 18089$-$1732

Abstract: The observation of oxygen (O)- and nitrogen (N)-bearing molecules gives an idea about the complex prebiotic chemistry in the interstellar medium (ISM). In this article, we present the identification of the rotational emission lines of N-bearing molecules ethyl cyanide (C${2}$H${5}$CN), cyanoacetylene (HC${3}$N), and O-bearing molecules methyl formate (CH${3}$OCHO) towards high-mass protostar IRAS 18089$-$1732 using the Atacama Compact Array (ACA). We also detected the emission lines of both N- and O-bearing molecule formamide (NH${2}$CHO) in the envelope of IRAS 18089$-$1732. We have detected the $v$ = 0 and 1 states rotational emission lines of CH${3}$OCHO. We also detected the two vibrationally excited states of HC${3}$N ($v$7 = 1 and $v$7 = 2). The estimated fractional abundances of C${2}$H${5}$CN, HC${3}$N ($v$7 = 1), HC${3}$N ($v$7 = 2), and NH${2}$CHO towards the IRAS 18089$-$1732 are (1.40$\pm$0.5)$\times$10$^{-10}$, (7.5$\pm$0.7)$\times$10$^{-11}$, (3.1$\pm$0.4)$\times$10$^{-11}$, and (6.25$\pm$0.82)$\times$10$^{-11}$. Similarly, the estimated fractional abundances of CH${3}$OCHO ($v$ = 0) and CH${3}$OCHO ($v$ = 1) are (1.90$\pm$0.9)$\times$10$^{-9}$ and (8.90$\pm$0.8)$\times$10$^{-10}$, respectively. We also created the integrated emission maps of the detected molecules, and the observed molecules may have originated from the extended envelope of the protostar. We show that C${2}$H${5}$CN and HC${3}$N are most probably formed via the subsequential hydrogenation of the CH${2}$CHCN and the reaction between C${2}$H${2}$ and CN on the grain surface of IRAS 18089$-$1732. We found that NH${2}$CHO is probably produced due to the reaction between NH${2}$ and H${2}$CO in the gas phase. Similarly, CH${3}$OCHO is possibly created via the reaction between radical CH$_{3}$O and radical HCO on the grain surface of IRAS 18089$-$1732.