ABUNDANCES AND RADIAL GRADIENTS FROM DISK PLANETARY-NEBULAE - HE, N, C, AND CL

Chemical abundances of the elements He, N, C, and Cl are presented for disk planetary nebulae, comprising Peimbert types I, II, and III, Ave rage abundances for these classes are determined and compared with the remaining abundances available. The presence of abundance gradients r elative to hydrogen for disk nebulae is investigated in a region of ab out 8 kpc centered in the solar system. It can be concluded that the g radients of the ratios N/H, Cl/H, and probably C/H are similar to the O/H gradient, especially for type II objects.