Radiative He⁺(1s) + He(1s²) processes as the source of the DB white dwarf atmosphere electromagnetic continuous spectra

Abstract

The influence of the processes of radiative charge transfer and photoassociation during He+ +He collisional processes, as well as the process of the photodissociation of the He2+ molecular ion, on the formation of the continuous spectrum of the DB white dwarf atmospheres with Teff = 12,000-30,000 K, for log g (gravity) = 7 and 8, is studied within the wavelength range λ= 200-800 nm. It is shown that the contribution of these processes relative to other relevant radiative processes is particularly important for Teff ≤ 16,000 K and increases with the decrease of Teff. Moreover, it is found that the influence of the considered He+ + He radiative processes is particularly pronounced in the UV range.