Onion-like physical models. (a) The spherical model with the layer width as $10\sqrt{2}$ arcsec (≈14.1″ and 1980 au at the distance of 140 pc, the same as the spacing of IRAM 30-m/GBT pointing observations) and (b) the asymmetric model overlaid on the contours of the 850 µm map. The contour levels are 20%, 40%, 60%, and 80% of the peak at 78 mJy beam⁻¹. (c) 3D visualization of the H₂ density distribution in the asymmetric model.