Second model for IRC +10420 with high gas density and low NH₃ abundance. Top left: input gas density and NH₃ abundance profiles. Only the radii with abundance >10⁻¹⁰ are plotted. Top right: input gas and dust temperature profiles. Middle: radial intensity profiles of NH₃ (1, 1) (left) and NH₃(2, 2) (right) at the velocity channel VLSR = 65 km s−1, which showthe strongest emission in both rotational and inversion transitions. Bottom: radial intensity profiles of NH₃ (1, 1) (left) and NH₃(2, 2) (right) at the velocity channel VLSR = 75 km s−1, which is the systemic velocity of IRC +10420. In the radial intensity profiles, black points indicate the binned data points from the VLA images and red curves show the modelled profiles.