Mid and Far Infrared Photometry of Galactic Planetary Nebulae with the
  AKARI All Sky Survey
  We provide mid- and far-infrared photometry of 857 Galactic planetary nebulae
(PNe) using data derived from the AKARI All-Sky Survey. These include fluxes at
9 and 18 {\mu}m obtained with the Infrared Camera (IRC), and at 65, 90, 140 and
160 {\mu}m using the far-Infrared Surveyor (FIS). It is noted that the IR
luminosities of the youngest PNe are comparable to the total luminosities of
the central stars, and subsequently decline to ~ 5102 L where D > 0.08 pc. This
is consistent with an evolution of PNe dust opacities, and appreciable
absorption in young and proto-PNe. We also note that whilst there is little
evidence for the evolution in IR/radio flux ratios suggested by previous
authors. The fall-off in dust temperatures is similar to that determined in
previous studies, whilst levels of Ly heating are < 0.5 of the total energy
budget of the grains. There appears to be an evolution in the infrared excess
(IRE) as nebulae expand, with the largest values occurring in the most compact
PNe.
