Abundances of selected gas-phase (top panels) and ice (bottom panels) molecules with respect to H₂ as a function of the radius in simulations M_TD, M_10, and M_0. Profiles are shown for two different values of the central H₂ density: 10⁵ (red) and 10⁷ cm⁻³ (blue). Solid, dashed, and dotted lines correspond to simulation M_TD, M_10, and M_0, respectively. The central density of 10⁵ cm⁻³ corresponds to t = 5.50 × 10⁵ yr, t = 5.57 × 10⁵ yr, and t = 5.74 × 10⁵ yr in simulations M_TD, M_10, and M_0, respectively. The corresponding values for central density 10⁷ cm⁻³ are given in Table 4.