JHK photometry of planetary nebulae.

Infrared (JHK) photometry is presented for 80 planetary nebulae. Sixty-two of these have infrared colors which are dominated by hydrogen and helium plasma emission, while only 12 show the effects of thermal dust emission to a greater or lesser extent. All of the nebulae are classified according to whether the principal source of infrared emission is nebular, stellar, dust, or some combination of these three. A few peculiar objects are noted. A correlation is found between (J-H) sub-0 and He(+)/H. This arises because the J band includes the strong He I triplet line at 1.083 microns.