Observing Compact Disks Inside Pre-Planetary Nebulae with the Very Large Telescope Interferometer

Abstract

AGB stars appear to lose mass spherically, but many PNe resulting from the AGB mass-loss have non-spherical morphologies. Compact disks have been found in some bipolar PNe, but their role in the shaping process remains unknown. Compact Keplarian disks are found to be common around post-AGB binaries, however, these objects may never develop into PNe. Another group of post-AGB stars, known as pre-PNe, are surrounded by collimated nebulae shining by reflected light or shock ionisation. We are observing the inner circumstellar regions of pre-PNe at high angular resolutions with the VLTI. We seek to compare pre-PNe disks to those around other post-AGB stars and PNe. New observations of the pre-PN, IRAS 16279-4757, show evidence for a disk similar to those seen in young PNe.