Species abundance comparison between the fiducial MHD model and the lower temperature model. The starting time of the figure has been set to 5×l0⁴ years to show a closer detail of the major changes. Left: fiducial MHD model. In the fiducial case, we observed that the chemistry is mostly inherited from the ices. Once the molecules sublimate (at ~5.4×l0⁴ years) their abundances remain almost constant, except for CS₂ and S₂. Right: lower temperature model. In this model, different molecules sublimate at different temperatures, and some need a few thousand years to stabilize their gas-phase abundance (e.g., CS₂, SO, SO₂ and H₂CS). After ~5.8×l0⁴ yr, H₂S abundance starts to fall, while H₂S₂ and S₂ start to form. In particular, S₂ increases its abundance abruptly by several orders of magnitude, reaching an abundance of ~10^–6, which is 10⁴ times more than in the fiducial case.