2025RNAAS...9...14R

“Very fast” novae, with their high ejection velocities, smaller ejecta masses, high photospheric temperatures, and rapidly changing conditions are generally inhospitable to the formation and survival of dust. Here we present infrared spectra from multiple epochs of a rare exception, the nova V2361 Cygni. With its time to decline from peak visible brightness by two magnitudes (t₂) of 6 days, V2361 Cygni is the third fastest nova known to have formed dust. At 23 days after peak brightness, its spectrum was dominated by emission from 1000 K dust with a luminosity of 1.6 × 10⁴ L_⊙. The dust persisted for an extended period and thermal emission was still prominent at 140 and 152 days post maximum. In another rarity, at those later two epochs V2361 Cygni exhibited coronal lines concurrent with its dust emission.