  We consider supercritical accretion onto a compact object when the accretion
rate exceeds its value derived from the Eddington limit: L_{Edd}/c^2. We use
the scenario that was proposed by Shakura and Sunyaev (1973) for the
supercritical regime, according to which matter flows out of the gas-disk
surface under radiation pressure. An analytic solution of the accretion-disk
structure is obtained for this scenario by using classical equations. An
attempt is made to construct a model for nonconservative supercritical
accretion with advection. To this end, we develop a numerical scheme for
calculating the structure of an advective disk with mass outflow. The goal of
solving the problem of a supercritical disk with mass loss is to explain
accreting sources with outflowing envelopes, for example, SS 433 and galactic
nuclei. The structure and observational manifestations of the envelope which
forms around a supercritical disk are considered by taking into account
bremsstrahlung absorption and Thomson scattering of photons.
