Radial profile of observed H¹³CN(1−0) and HN¹³C(1−0) integrated intensities (upper and lower panel, respectively) and model prediction for a core with a central hole of 8  ×  10¹⁶ cm and an outer abundance value of 1.7  ×  10^-10 (red solid lines) and 2.04  ×  10^-10 (blue dashed line). HN¹³C(1−0) data come from this study and H¹³CN(1−0) data come from this study and Tafalla et al. (2006).