An analytic self-gravitating disk model: inferences and logical structure

Abstract

The foundations of an analytic Accretion-Decretion (A-D) disk model, based on equipotential theory, for mass-transfer binaries are examined. Gravitation of stars 1 and 2 and the disk, as well as disk and star rotation, are included and relevant morphology is explored. Expected applications are to disks with morphologically significant mass and substantial optical thickness. Anticipated targets include classical novae, nova-like variables, and W Serpentis binaries, with the concept invoking knowledge about Be stars and the classically strange binary β Lyrae. The model’s ideas and resulting character differ from those usually applied to optically thick disks – for example there is no need to truncate the model arbitrarily at an outer or inner limit, because it closes naturally at both places. The disk is a volume emitter with attenuation of internally generated light. Computations intrinsically produce phenomena that are characteristic of circumstellar disks in binaries – in particular tidal and rotational gravity brightening and an outer effective gravity null point that do not occur in the common axisymmetric disk model. Impersonal analysis in terms of the model (Least Squares criterion) is applied to light curves of recurrent nova CI Aquilae.