Comparison of deuterium fraction fromobservations and actrochemical model for cold dense cores

In this work, we present a comparison of the column densities and deuterium fractions of species from observations and from an astrochemical model. The following pairs of species were chosen for comparison: N2H+ and N2D+, H13CO+ and DCO+, NH3 and NH2D. The observations were performed with the IRAM-30m telescope towards four cold dense cores: Oph-E-MM2, Oph-C-N, Oph-H-MM1, and Oph-F. The observed column densities were calculated with the assumption of local thermodynamic equilibrium. The modelled column densities were calculated with the PyRate3 model [1]. Temperature and density profiles for the selected cores were constructed for the model. As a result of the comparison, the column densities and deuterium fractions from the model are similar to the column densities and deuterium fractions from observations at the moment of the peak deuterium fraction. We estimated the chemical ages of the dense cores from the deuterium fraction peaks, with median ages of 2.65 • 10‘, 2.65 • 10‘, 0.82 • 10‘ and 1.80 • 10‘ years for Oph-C-N, Oph-E-MM2, Oph-F, and Oph-H-MM1, respectively. The more detailed results are presented in work [2].