Extended Data Fig. 8: Dominant CH3+ formation and destruction reactions at the CH3+ abundance peak predicted by the photochemical model shown in Fig. 7.
From: Formation of the methyl cation by photochemistry in a protoplanetary disk
This reaction network also leads to abundant HCO+ in FUV-irradiated gas layers where x(C+) > x(CO). Red arrows show endoergic reactions when H2 is in the ground-vibrational state v = 0. These reactions become fast only in disk layers where the gas temperature is high (several hundred K) and/or significant vibrationally excited H2* (v ≥ 0) exists. The formation of CH3+ from methane will only be relevant if very high CH4 and H+ abundances coexist in the gas.
