2008 Supplement: Frascati Workshop 2007 / Church

The Importance of Radiation Pressure in the Launching of Jets

M. J. Church, N. K. Jackson, M. Bałucińska-Church


Based on the results of applying the extended ADC emission model to
three Z-track sources: GX 340+0, GX 5-1 and Cyg X-2, we propose an
explanation of the Z-track sources in which the Normal and Horizontal
Branches are dominated by the increasing radiation pressure of the
neutron star. The emitted flux becomes several times super-Eddington at
the Hard Apex and Horizontal Branch and we suggest that the inner
accretion disk is disrupted by this and that part of the accretion flow
is diverted vertically. This position on the Z-track is exactly the
position where radio emission is detected showing the presence of jets.
We thus propose that high radiation pressure is a necessary condition
for the launching of jets. We also show that flaring must consist of
unstable nuclear burning and that the mass accretion rate per unit
emitting area of the neutron star dot m at the onset of flaring agrees
well with the critical theoretical value at which burning becomes


physical data and processes: acceleration of particles physical data and processes: accretion: accretion disks stars: neutron stars: individual: GX 340+0 GX 5-1 Cyg X-2 X-rays: binaries

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