The close DAO+dM binary RE J0720-318: a stratified white dwarf with a thin H layer and a possible circumbinary disk

Matthew R. Burleigh, Martin A. Barstow, Paul D. Dobbie

We have analysed the EUVE spectrum of the DAO white dwarf RE J0720-318. In contrast to the optical spectrum, which can only be fitted with a homogeneously mixed atmosphere, we find…