Gallery of S/N maps from few of the observed lines used in this work. The line name is indicated on the top of each panel while their beam is shown in the lower right corner. The star indicates the position of L1489 IRS. The cyan contour corresponds to the targeted emission for the analysis (see Sect. 3.2). The black cross indicates the position of the peak intensity of the core (Wu et al. 2019). Top to bottom: IRAM-30m observations of HC₃N (first panel), single-field combined observations (IRAM-30m + NOEMA) of HC₃N (second), C₂H (third), and c-C₃H₂ (fourth), and mosaic combined observations of c-C₃H₂ (fifth).