Constraining inputs to realistic kilonova simulations through comparison to observed $r$-process abundances

M. Ristic, E. Holmbeck, R. T. Wollaeger, O. Korobkin, E. Champion, R. O'Shaughnessy, C. L. Fryer, C. J. Fontes, M. Mumpower, T. M. Sprouse

Submitted ApJ 956 1 (2023)

Kilonovae, one source of electromagnetic emission associated with neutron star mergers, are powered by the decay of radioactive isotopes in the neutron-rich merger ejecta. Models for kilonova emission consistent with available modeling and the electromagnetic counterpart to GW170817 also predict characteristic abundance patterns, determined by the relative balance of different types of material in the outflow. Assuming the observed source is prototypical, this inferred abundance pattern in turn must match r -process abundances deduced by other means, such as what is observed in the solar system. We report on analysis comparing the input mass-weighted elemental compositions adopted in our radiative transfer simulations to the mass fractions of elements in the Sun. We characterise the extent to which our parameter inference results depend on our assumed composition for the dynamical and wind ejecta and examine how the new results compare to previous work. We find that a mass ratio of $M_w$ / $M_d$ = 2.81 reproduces the observed AT2017gfo kilonova light curves while also producing the abundance of neutron-capture elements in the solar system.