2023RNAAS...7..277R

Optical and near-infrared spectra of the classical nova V1405 Cassiopeiae (V1405 Cas) from more than two years after outburst show a still bright nova of intermediate excitation with coronal lines, some high-ionization but non-coronal forbidden lines, and very strong emission features of He II. However, the common nebular lines of [N II], [O II], and [O III] are absent and the lines of He I are very weak. Analysis with the photoionization code CLOUDY indicates a emission line region that is sharply matter-bounded, truncating before the gas excitation drops sufficiently to support the parent ions of lower excitation lines.