Comparison between the internally heated clump with the fiducial E-CH₃OH methanol abundance of 10⁻⁹ (yellow shaded areas), the low-abundance (E − CH₃OH/H₂ = 10⁻¹⁰, 1/10 fiducial), low-optical depth case (green shaded areas) and the high-abundance (E − CH₃OH/H₂ = 10⁻⁸, 10 times fiducial), high-optical depth case (blue shaded areas). The light-shaded areas correspond to the 90% HPD, while the dark shaded areas correspond to the 50% HPD.