DYNAMICS OF THE CHELYABINSK METEOROID ENTERING THE ATMOSPHERE: MASS-ENERGY BALANCE

Purpose: The study is concerned with determining the height and temporal dependences of the Chelyabinsk meteoroid surface temperature, its emission rate and energy losses, as well as calculations of its ablation parameters, the coefficient of dynamical resistance, and the correction to the height-time dependence of the midsection. Design/methodology/approach: Numerical calculations have been made of the meteoroid temperature with accounting for the preliminary estimates of the midsection and of the total optical emission intensity, whith the optical corrections taken into account. The conditions for estimating the dynamical resistance have been determined. The corrected height-time dependence of the midsection has been calculated with the known mass loss rate. The implementation of the regularization algorithm utilizes the energy balance. Findings: The balance of energy losses includes the equations of meteor physics taking into account the deceleration force, the ablation processes, emissions, and the detachment of the meteoroid fragments. The height-time dependences of temperature, emission rates, and the midsection have been obtained. The successive iterations in the regularization algorithm resulted in the corrections to the magnitude of the coefficient of dynamical resistance, the specific ablation energy, and the heat transfer coefficient. The branching ratio for the total kinetic energy is as follows: 16.8 % for air resistance, 8 % for emissions, 8.2 % for ablation and defragmentation, and 67 % for the kinetic energy of the detached fragments. Conclusions: Numerical simulations have provided the height and temporal dependences of mass, midsection, emission rates, and meteoroid temperature. The ablation parameters and the dynamical resistance coefficient have been estimated. A balance among energy loss processes associated with the Chelyabinsk meteoroid entering the atmosphere has been constructed.