2022ApJ...925..187P

We perform photoionization modeling of the dusty nova V1280 Scorpii (V1280 Sco) with the aim to study the changes in the physical and chemical parameters. We model the predust and postdust phase and optical and near-infrared spectra using the photoionization code CLOUDY, v.17.02, considering a two-component (low-density and high-density regions) model. From the best-fit model, we find that the temperature and luminosity of the central ionizing source in the predust phase is in the range 1.32-1.50 x 10⁴ K and 2.95-3.16 x 10³⁶ ergs^–1, respectively, which increase to 1.58-1.62 x 10⁴ K and 3.23-3.31 x 10³⁶ ergs^–1, respectively, in the postdust phase. It is found that a very high hydrogen density (∼10¹³-10¹⁴ cm^–3) is required for the proper generation of spectra. Dust condensation conditions are achieved at high ejecta density (∼3.16 x 10⁸ cm^–3) and low temperature (∼2000 K) in the outer region of the ejecta. It is found that a mixture of small (0.005-0.25 µm) amorphous carbon dust grains and large (0.03-3.0 µm) astrophysical silicate dust grains is present in the ejecta in the postdust phase. Our model yields very high elemental abundance values as C/H = 13.5-20, N/H = 250, O/H = 27-35, by number, relative to solar values, during the predust phase, which decrease in the postdust phase.