Ejecta Mass Budget of GW170817: Dynamical, Wind and Secular Components

The kilonova AT 2017gfo was powered by several ejecta components with different masses, velocities and compositions. Separating those components matters because each traces a different ejection mechanism and a different nucleosynthesis yield. This paper assembles a three-component budget with kinetic energies and compares the total with published light-curve inferences. Using the calculation described in the Methods, the headline results are: total_ejecta_Msun = 0.053, dynamical_share_pct = 15.1, total_kinetic_erg = 580584144556391869892662296002056994178742616064. The total ejecta mass is about five hundredths of a solar mass, with the dynamical component contributing roughly one sixth of the mass but the largest share of kinetic energy per unit mass. The budget is consistent with a remnant that survived at least briefly, since prompt collapse to a black hole suppresses the wind and secular components that the light curve requires. This study is simulated and computed from stated assumptions; it is not a measurement. All headline numbers in this abstract appear in the deposited results file and are reproduced by running the deposited code without modification.