Optically thick winds in classical novae

The photospheric properties of continuously outflowing optically thick winds are derived using Christy's (1966) fit to the Cox–Stewart opacities and an approximate treatment of scattering under translucent conditions. The decline behavior of classical novae has been synthesized by photospheric sequences in which the mass-loss rates slowly decrease and the wind progressively thins. The conclusions of earlier models based on pure scattering opacities are generally confirmed. The resulting retreat of the photospheric layers and increase in the photospheric temperature as the wind thins leads to progressive photoionization of ions of increasing ionization potential and an associated fall in the optical continuum. The relation derived between the decline stage and the first possible emergence of specific emission lines is in approximate agreement with that of normal novae.