Incomplete understanding of key kilonova microphysics (opacity, heating, thermalization)

Characterize the wavelength-dependent ejecta opacities, the radioactive nuclear heating rates, and the thermalization efficiencies governing kilonova emission in order to reduce modeling uncertainties and enable reliable inference of ejecta masses and velocities from observed light curves.

Background

The authors emphasize that some fundamental ingredients of kilonova modeling are not yet well constrained, which directly affects parameter inference. In particular, degeneracies among ejecta mass, velocity, and opacity, combined with time- and temperature-dependent opacity variations, introduce systematic uncertainties.

They note that even state-of-the-art simulations still lack precise understanding of these microphysical quantities, which limits confident mapping from observational data to physical ejecta properties.