Program: GN-2005A-Q-64

It has long been suspected that binary stars must play a role in shaping the collimated outflows observed from many, if not all, post-AGB stars. Models of mass-loss in a binary system predict the formation of circumstellar or circumbinary discs, which may mediate the outflow shaping. To study disc formation and the role of discs in outflow shaping, we propose to use AO imaging with NIRI in the J and K bands. We have selected targets with strong evidence of axisymmetry in their dust envelopes and with optically bright central stars, to enable efficient AO correction on-source. We expect to be able to image structure in the envelopes on a scale of 100 AU at 1 kpc, or to within 0.1 arcsec of the star. By constructing detailed disc models we will provide much needed constraints to current theories of disc formation and outflow collimation in binary systems.