On the Inaccuracy of Astrochemical Modeling Using Various Reaction Kinetics Databases

The paper examines the impact of evolutionary changes in the UDfA astrochemical databases on the uncertainty of molecular abundance modeling in astrochemical simulations. This uncertainty was assessed through statistical analysis of the results of molecular abundance modeling performed using varied reaction rate constants. The modeling was performed for conditions typical of dark clouds and the methanol peak region of a protostellar core, under static physical parameters of the medium. The calculations were performed using the MONACO code for gas-phase chemistry only. Variance curves were obtained for the logarithms of the abundances of hydrocarbons, as organic molecules capable of forming in the gas phase. Analysis of the histograms of variances’ statistical distributions for different databases demonstrates that increasing the number of reactions and refining their parameters in modern versions of the databases generally does not affect changes in particles’ variances. The dependence of the variance on the complexity of the molecular formation chains is confirmed: more complex molecules show a greater variance of their abundance.