A model for the spectrum of Sakurai's object (V4334 Sgr)

Theoretical spectral energy distributions for Sakurai's object at 300-1000 nm are derived. A model-atmosphere grid with T-eff = 5000-6250 K and log g = 0.0-1.0 is computed for the chemical composition of Sakurai's object usin g opacity sampling including molecular and atomic absorption. Opacity due t o absorption in 20 band systems of diatomic molecules is computed using the JOLA technique. The theoretical fluxes are compared with the observed ener gy distribution in a spectrum of Sakurai's object taken in April 1997. It i s shown that (a) the theoretical energy distributions agree well qualitativ ely with the observed spectrum and depend strongly on the effective tempera ture; (b) C-2 and CN molecular bands are dominant in the visible and near-i nfrared spectrum, while atomic absorption is important at UV and blue wavel engths; and (c) comparison of the observed and computed spectra yields an e ffective temperature for Sakurai's object in April 1997 T(eff)approximate t o 5250-5500 K. The dependence of the computed spectra at 300-1000 nm on the input parameters and adopted approximations is also discussed. (C) 2000 MA IK "Nauka/Interperiodica".