ALMA detection of complex nitrile species ethyl cyanide in the high mass star formation region IRAS 18566+0408

The study of high-mass star formation objects demonstrates valuable details about the chemical composition and massive star formation process. We present the spectroscopic detection of the rotational molecular emission lines of complex nitrile species ethyl cyanide in the high mass star-forming region IRAS 18566+0408 using the Atacama Large Millimeter/Submillimeter Array (ALMA). We detected a total of thirteen rotational emission lines of ethyl cyanide including their different $^{13}C$ isotopologue between the frequency range of $ u$ = 86$-$111 GHz with ALMA band 3 observation. Using LTE model, the range of statistical column density of ethyl cyanide is found (3$-$4)$times$10$^{15}$ cm$^{-2}$ with rotational temperature $T_{rot}$ = 90 K. The abundance of ethyl cyanide in IRAS 18566+0408 relative to the H$_{2}$ is estimated between the range of (1.0$-$1.4)$times$10$^{-8}$ where $N$(H$_{2}$) = 2.9$times$10$^{23}$ cm$^{-2}$.