On the chemistry of the young massive protostellar core NGC 2264 CMM3

We present the first gas-grain astrochemical model of the NGC 2264 CMM3 protostellar core. The chemical evolution of the core is affected by changing its physical parameters such as the total density and the amount of gas-depletion onto grain surfaces as well as the cosmic ray ionisation rate, \(\zeta\). We estimated \(\zeta_{\text{CMM3}} = 1.6 \times 10^{-17}~\mbox{s}^{-1}\). This value is 1.3 times higher than the standard CR ionisation rate, \(\zeta _{\text{ISM}} = 1.3 \times 10^{-17}~\mbox{s}^{-1}\). Species response differently to changes into the core physical conditions, but they are more sensitive to changes in the depletion percentage and CR ionisation rate than to variations in the core density. Gas-phase models highlighted the importance of surface reactions as factories of large molecules and showed that for sulphur bearing species depletion is important to reproduce observations.