Notes. For the density and composition, we take a spherical average of velocity shells from the N5def model of Fink et al. (2014). The naming scheme of our models is defined as follows: N5-XT refers to TARDIS models (“T”) which are based on the N5def model from Fink et al. (2014), with “-X” referring to the phase of the spectrum. These times correspond to phases of −3 d, −2 d, and + 2 d relative to r-band maximum, assuming a rise time of ~22  (Phillips et al. 2007; Magee et al. 2016). The suffixes f/s refer to the photospheric velocity being fast/slow, while h/l refer to the ejecta density being higher/lower relative to the N5def model.