Ionization structure of hot components in symbiotic binaries during active phases
Authors:
Z. Carikova, A. Skopal
Image & caption:
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Image caption::
Model of the ionization structure of the hot components in symbiotic binaries during active phases as seen on a cut perpendicular to the orbital (x,y) plane containing the WD, which spins along the z-axis. The neutral zone has the form of a flared disk. It is optically thick to the distance Rd. The inplot figures the central WD as a black circle and its pseudophotosphere as a shadow circle.
Description:
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. In this paper we aimed to explain how such the formation can be created during active phases. Our concept is based on the fact that during active phases the mass loss rate from the hot star (i.e. the white dwarf – WD) increases by a factor of ~10 and the assumption that the WD can rotate fast. The fast rotation of the source of the stellar wind causes its compression to the equatorial plane, where it can form a neutral disk-like region flared from its centre. The remainder of the sphere above/below the disk is ionized. Basic parameters of the model (the mass loss rate, emission measure of the ionized zone and the hydrogen column density of the neutral zone) are in a good agreement with those derived independently from observations. During quiescent phases, the neutral disk-like structure cannot be created, because the mass loss rate and thus the compression are insufficient. This mechanism probably represents a common origin of warm pseudophotospheres, indicated in the spectrum of active symbiotic binaries.
Reference:
Astronomy & Astrophysics, 548, article no. A21, p. 1-10 (2012)
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