Deuterium chemodynamics of massive pre-stellar cores

ABSTRACT High levels of deuterium fractionation N2H+ (i.e. $\mathrm{D^{{\mathrm{N_2H^+}}}_{\text{frac}}}$≳ 0.1) are often observed in pre-stellar cores (PSCs) and detection N2D+ is a promising method to identify elusive massive PSCs. However, the physical chemical conditions required reach such high deuteration still uncertain, as diagnostic utility observations We perform 3D magnetohydrodynamics simulations massive, turbulent, magnetized PSC, coupled with sophisticated astrochemical network. Although core has some magnetic/turbulent support, it collapses under gravity about one free-fall time, which marks end simulations. Our fiducial model achieves relatively low $\mathrm{D^{{\mathrm{N_2H^+}}}_{\text{frac}}}$∼0.002 during this time. then investigate effects initial ortho-para ratio H2 ($\mathrm{OPR^{H_2}}$), temperature, cosmic ray (CR) ionization rate, CO N-species depletion factors, prior PSC evolution. find that CR rates factors allow simulated $\mathrm{D^{{\mathrm{N_2H^+}}}_{\text{frac}}}$ absolute abundances match observational values within For $\mathrm{OPR^{H_2}}$, while lower value helps growth $\mathrm{D^{{\mathrm{N_2H^+}}}_{\text{frac}}}$, spatial structure too widespread compared systems. an example elevated significant heavy element depletion, we study kinematic dynamic properties traced by its emission. The core, undergoing quite rapid collapse, exhibits disturbed kinematics average velocity map. Still, because magnetic appears kinematically subvirial based on dispersion.