During active phases of symbiotic binaries, an optically thick medium in the
form of a flared disk develops around their hot stars. During quiescent phases,
this structure is not evident. We propose the formation of a flared neutral
disk-like structure around the rotating white dwarf (WD) in symbiotic binaries.
We applied the wind compression model and calculated the ionization boundaries
in the compressed wind from the WD using the equation of photoionization
equilibrium. During active phases, the compression of the enhanced wind from
the rotating WD can form a neutral disk-like zone at the equatorial plane,
while the remainder of the sphere above/below the disk is ionized. Calculated
hydrogen column density throughout the neutral zone and the emission measure of
the ionized fraction of the wind are consistent with those derived from
observations. During quiescent phases, the neutral disk-like structure cannot
be created because of insufficient mass loss rate. Formation of the neutral
disk-like zone at the equatorial plane is connected with the enhanced wind from
the rotating WD, observed during active phases of symbiotic binaries. This
probably represents a common origin of warm pseudophotospheres, indicated in
the spectrum of active symbiotic binaries with a high orbital inclination.Comment: 10 pages, 6 figures, accepted for publication in Astronomy and
Astrophysic
