Observing disks around post-AGB stars

Abstract:
We propose and test the hypothesis that disks found in pre-planetary nebulae (pre-PNe) will be different than those around close 
post-asymptotic giant branch (post-AGB) binaries. Observations of eight pre-PNe have been completed using the Very Large  
Telescope Interferometer (VLTI). The observations obtained are interpreted using geometrical and radiative transfer models. For 
two pre-PN, disks have definitely been identified and their size, shape, composition and mass have been characterised. For the 
remaining pre-PNe, limits have been imposed on the size of possible disks. The disk found inside the pre-PNe, IRAS 16279-4757, is 
much larger than the compact disks around close post-AGB binaries, is likely not in a stable, Keplerian orbit, and may be from a 
wide-binary companion. Inside the second pre-PNe, IRAS 08005-2356, the disk is found to be very similar to the compact disks 
found around close post-AGB binaries and may be a unique cross-over object.